| 单词 | hydroxyl |
| 例句 | That’s because hydrogen reacts with and depletes hydroxyl radicals, chemical species in the atmosphere that play a key role in breaking down methane. Carbon-free fuels could have a dark side 2023-11-14T05:00:00Z In the end, swapping the position of a hydrogen atom and a hydroxyl group on the backbone of the molecule blocked its ability to bind to cholesterol. New antifungal kills without toxic side effects 2023-11-08T05:00:00Z Figure 9.5 The difference between the ribose found in RNA and the deoxyribose found in DNA is that ribose has a hydroxyl group at the 2' carbon. Concepts of Biology 2013-04-25T00:00:00Z But the issue with most methods of detection is that they cannot tell the difference between water, which is made up of hydrogen and oxygen, and hydroxyl, another hydrogen-containing compound. The Ethiopian scientist on the search for water on the moon 2022-11-19T05:00:00Z If the hydroxyl group was not present, we would have named this molecule pentane. Chemistry 2019-02-14T00:00:00Z Some of the important functional groups in biological molecules are shown in Figure 2.29; they include: hydroxyl, methyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl. Biology for AP Courses 2022-06-09T00:00:00Z When hydrogen ions in the wind strike oxygen-bearing minerals in lunar soil, it creates hydroxyl, which can be transformed into water through subsequent reactions. Stowaways on NASA’s massive Moon rocket promise big science in small packages 2022-08-15T04:00:00Z Fluoride can displace the hydroxyl group in bone’s hydroxyapatite crystals and form fluorapatite. Anatomy and Physiology 2013-06-19T00:00:00Z The researchers also detected short-lived molecules called radicals, like hydroxyl and hydroperoxyl, that are known to drive reactions that create particles outdoors. Mopping can create air pollution that rivals city streets 2022-02-24T05:00:00Z It can also create reactive hydroxyl radicals that damage biological molecules and disrupt physiological processes. Chemistry 2019-02-14T00:00:00Z During this process, the hydroxyl group of one monosaccharide combines with the hydrogen of another monosaccharide, releasing a molecule of water and forming a covalent bond. Biology for AP Courses 2022-06-09T00:00:00Z Lunar IceCube will carry a spectrometer that can detect the infrared fingerprints of either water or hydroxyl. Stowaways on NASA’s massive Moon rocket promise big science in small packages 2022-08-15T04:00:00Z One portion of the severed compound then bonds with the hydrogen atom, and the other portion bonds with the hydroxyl group. Anatomy and Physiology 2013-06-19T00:00:00Z Lab experiments show that adding iron to sprays of seawater can boost production of both chlorine and hydroxyl and significantly speed up methane destruction. To slow global warming, some researchers want to pull methane out of the air 2021-11-02T04:00:00Z Because the hydroxyl radical has an unpaired electron, it is highly reactive. Chemistry 2019-02-14T00:00:00Z The difference between the sugars is the presence of the hydroxyl group on the second carbon of the ribose and hydrogen on the second carbon of the deoxyribose. Biology for AP Courses 2022-06-09T00:00:00Z Because the device depends on reflected light, it will be most sensitive to signs of hydroxyl and water in sunlit regions at lower latitudes. Stowaways on NASA’s massive Moon rocket promise big science in small packages 2022-08-15T04:00:00Z Strong bases release most or all of their hydroxyl ions; weak bases release only some hydroxyl ions or absorb only a few H+. Anatomy and Physiology 2013-06-19T00:00:00Z Some of this iron bunches together and reacts with naturally occurring hydrogen peroxide to produce hydroxyl radicals—highly reactive molecules that can harm cells. Cigarette Smoke Kills Eye Cells 2021-10-18T04:00:00Z Alcohols containing two or more hydroxyl groups can be made. Chemistry 2019-02-14T00:00:00Z Polymers break by separating water into hydrogen and hydroxyl group that are added to the monomers. Biology for AP Courses 2022-06-09T00:00:00Z Some devices generate ozone — yes, that ozone, a respiratory hazard — while others produce dangerous hydroxyl radicals that may injure cells. How to Keep the Coronavirus at Bay Indoors 2020-09-27T04:00:00Z Each monomer contributes: One gives up a hydrogen atom and the other gives up a hydroxyl group. Anatomy and Physiology 2013-06-19T00:00:00Z Instead, Comber is looking at the introduction of hydroxyl radicals into indoor air. 'My company has gone fully remote and I'm despairing': who wins in the new world of working from home? 2020-09-12T04:00:00Z Morphine, a strong narcotic used to relieve pain, contains two hydroxyl functional groups, located at the bottom of the molecule in this structural formula. Chemistry 2019-02-14T00:00:00Z Polymers are synthesized by using the energy released by the breaking of water molecules into hydrogen and hydroxyl group. Biology for AP Courses 2022-06-09T00:00:00Z The authors also discovered that one of the candidate cytochrome P450 enzymes catalyses two steps in the proposed biosynthetic pathway: the installation of two hydroxyl groups on a benzene ring in an intermediate compound. How the flame lily synthesizes a therapeutic natural product 2020-07-21T04:00:00Z The bonds between their monomers are broken, via the donation of a molecule of water, which contributes a hydrogen atom to one monomer and a hydroxyl group to the other. Anatomy and Physiology 2013-06-19T00:00:00Z The facility has hired an industrial cleaning service to perform “daily deep cleaning” and installed six machines known as hydroxyl generators, which treat pathogens in the air and on surfaces. Washington region’s coronavirus death toll hits 51, a record 16 fatalities reported in one day 2020-03-29T04:00:00Z Changing one of these hydroxyl groups to a methyl ether group forms codeine, a less potent drug used as a local anesthetic. Chemistry 2019-02-14T00:00:00Z Water, which was broken down into its hydrogen atom and hydroxyl group during ATP hydrolysis, is regenerated when a third phosphate is added to the ADP molecule, reforming ATP. Biology for AP Courses 2022-06-09T00:00:00Z Like many researchers, he’d assumed that indoor air, lacking sunlight and, thus, hydroxyl radicals, wouldn’t yield the kind of rapid photochemical reactions that atmospheric scientists like to study. The Hidden Air Pollution in Our Homes 2019-04-01T04:00:00Z Notice that glycerol gives up a hydrogen atom, and the carboxyl groups on the fatty acids each give up a hydroxyl group. Anatomy and Physiology 2013-06-19T00:00:00Z The particular hydroxyl groups found on Ryugu appear to be associated with the element magnesium, which is often associated with clay minerals in meteorites. Asteroid mission exploring a 'rubble pile' 2019-03-19T04:00:00Z But the discovery of hydroxyls—molecules bonded with hydrogen and oxygen—is a promising start to the mission’s science phase. Getting the Dirt on Creation--Inside OSIRIS-REx's First Close Look at Bennu 2018-12-19T05:00:00Z When a polynucleotide is formed, the 5′ phosphate of the incoming nucleotide attaches to the 3′ hydroxyl group at the end of the growing chain. Biology for AP Courses 2022-06-09T00:00:00Z According to a press release regarding the discovery, scientists suspect that much of the asteroid’s minerals are full of “hydroxyls,” molecules that contain oxygen and hydrogen atoms bonded together. How NASA's OSIRIS-Rex spacecraft is helping Earthlings understand how we got here 2018-12-17T05:00:00Z Like other lipids, cholesterol’s hydrocarbons make it hydrophobic; however, it has a polar hydroxyl head that is hydrophilic. Anatomy and Physiology 2013-06-19T00:00:00Z The spacecraft’s two spectrometers revealed the presence of “hydroxyls,” which are molecules containing oxygen and hydrogen atoms bonded together. NASA makes amazing discovery on asteroid Bennu 2018-12-11T05:00:00Z Although studies of other atmospheric gases have been used to infer the abundance of hydroxyl over the past four decades, atmospheric chemists still refer to the chemical as ‘the great unknown’. The Hunt for Sky's "Detergent" Begins in Antarctica 2018-11-24T05:00:00Z There, they hope to capture the first historical data on concentrations of the dominant atmospheric detergent, the hydroxyl radical. Antarctic scientists begin hunt for sky’s ‘detergent’ 2018-11-19T05:00:00Z Specifically, he has examined hydroxyl radicals, which are water molecules stripped of one hydrogen atom. Scientists struggle to explain a worrying rise in atmospheric methane 2018-04-26T04:00:00Z Glycerol gives up hydrogen atoms from its hydroxyl groups at each bond, and the carboxyl group on each fatty acid chain gives up a hydroxyl group. Anatomy and Physiology 2013-06-19T00:00:00Z Instead, scientists gauge OH- abundance by looking to proxies— chemicals that react with hydroxyl. Why is atmospheric methane surging? (Hint: it's not fracking) 2016-12-21T05:00:00Z Up to now, information on historical trends in hydroxyl levels has come solely from atmospheric models; these simulations suggest that concentrations remained fairly stable from 1850 until the 1970s, when they started to rise. The Hunt for Sky's "Detergent" Begins in Antarctica 2018-11-24T05:00:00Z Although studies1 of other atmospheric gases have been used to infer the abundance of hydroxyl over the past four decades, atmospheric chemists still refer to the chemical as ‘the great unknown’. Antarctic scientists begin hunt for sky’s ‘detergent’ 2018-11-19T05:00:00Z The decrease in hydroxyls, they wrote last year in Proceedings of the National Academy of Sciences, is “the mathematically most likely explanation” for the rise in methane levels after 2006. Scientists struggle to explain a worrying rise in atmospheric methane 2018-04-26T04:00:00Z The charged regions of these molecules can bind hydrogen and hydroxyl ions, and thus function as buffers. Anatomy and Physiology 2013-06-19T00:00:00Z One of the most important of these is the destruction process involving the so-called hydroxyl radical. Methane surge needs 'urgent attention' - BBC News 2016-12-11T05:00:00Z Cyclodextrins are sugar molecules arranged in a ring such that the sugar’s hydroxyl groups are perpendicular to the plane of the ring. A faster, cheaper water filter, thanks to sugar 2015-12-21T05:00:00Z “We have been more or less in the dark when it comes to how hydroxyl has evolved from pre-industrial times to present day,” says Apostolos Voulgarakis, an environmental scientist at Imperial College London. Antarctic scientists begin hunt for sky’s ‘detergent’ 2018-11-19T05:00:00Z Because a way to measure atmospheric hydroxyl concentrations reliably has yet to be invented, he and his colleagues arrived at their conclusion based on the use of computer models. Scientists struggle to explain a worrying rise in atmospheric methane 2018-04-26T04:00:00Z Most commonly, the substance that absorbs the ions is either a weak acid, which takes up hydroxyl ions, or a weak base, which takes up hydrogen ions. Anatomy and Physiology 2013-06-19T00:00:00Z While better known as the atmospheric trace gas that protects us from much of the solar UV radiation, ozone is also an important source of hydroxyl radicals in the troposphere owing to photodissociation. New Source of Greenhouse Gas "Cleaners" Found on Clouds 2014-08-04T04:00:00Z Then these hydroxyl radicals quickly seek out any organic matter touching that surface and break it down into smaller molecules. There’s Money in Pollution “This new research endeavour can provide unprecedented information on hydroxyl variations in the deeper past, which is exciting.” Antarctic scientists begin hunt for sky’s ‘detergent’ 2018-11-19T05:00:00Z This removal of hydroxyl radicals shuts down the reaction that forms ozone. Ethanol Fuels Ozone Pollution 2014-04-30T20:50:00Z A buffer is a substance that prevents a radical change in fluid pH by absorbing excess hydrogen or hydroxyl ions. Anatomy and Physiology 2013-06-19T00:00:00Z The fuel is based on hydroxyl ammonium nitrate, which is slightly more efficient than the Swedish propellant. Green fuels blast off 2013-08-28T17:20:17.693Z By "water," the researchers don't mean liquid water, but hydroxyl, a chemical that includes the hydrogen and oxygen ingredients of water. Apollo Moon Rocks Challenge Lunar Water Theory 2013-02-19T20:15:00.250Z And accurate pictures of hydroxyl’s historical and current atmospheric concentrations are essential for developing better projections of its future levels, says Voulgarakis. Antarctic scientists begin hunt for sky’s ‘detergent’ 2018-11-19T05:00:00Z Aircraft instruments will be able to record pollution over the English Channel Dr Lee's own research is focused on the precise role played by a short-lived "radical" known as hydroxyl. Effort set to track air pollution 2012-08-08T21:13:08Z Acid ~, a neutral compound formed by the substitution of the amido group for hydroxyl in an acid. Webster's Unabridged Dictionary 2012-03-24T02:00:23.513Z Similarly to regular cellulose, ethyl cellulose is an indigestible chain of repeating glucose molecules; the only difference is that the hydroxyl groups of ethyl cellulose are modified into ethyl ether groups. Something to Chew On: Healthier Hot Dogs Substitute Cellulose for Saturated Fats 2012-03-19T20:45:00.267Z Because they found hydroxyl deep inside each sampled rock, the scientists say they have eliminated the solar wind moon water explanation, because those particles can penetrate the surface only slightly. Apollo Moon Rocks Challenge Lunar Water Theory 2013-02-19T20:15:00.250Z The scientists can then use the information to infer how hydroxyl levels in the Southern Hemisphere have changed over time. Antarctic scientists begin hunt for sky’s ‘detergent’ 2018-11-19T05:00:00Z The process requires replacing three of sugar’s hydroxyl groups with chlorine atoms. A Missouri Town's Sweet Dreams Sour 2012-01-05T20:30:59Z As the hydroxyl groups in aurin correspond to the amino groups in pararosaniline, two of these in the latter compound must be in the para position. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Ethanol has two carbon atoms linked to five hydrogen atoms, plus a hydroxyl group. Fuel options: The ideal biofuel 2011-06-22T21:50:40.910Z Phenylalanine and tyrosine are structurally identical except for the hydroxyl group on tyrosine that renders the residue phosphorylatable. [Technical Response] Response to Comment on ?Positive Selection of Tyrosine Loss in Metazoan Evolution? 2011-05-19T18:25:18.573Z Up to now, information on historical trends in hydroxyl levels has come solely from atmospheric models; these simulations suggest2 that concentrations remained fairly stable from 1850 until the 1970s, when they started to rise. Antarctic scientists begin hunt for sky’s ‘detergent’ 2018-11-19T05:00:00Z “Driving this chemistry,” Robinson notes, “was hydroxyl radical,” or OH—the oxidant that’s most effective at catalyzing the breakdown of oily hydrocarbons. Idling Jets Pollute More Than Thought 2011-05-11T15:10:00Z The water being present in excess, the hydrogen and hydroxyl are re-formed at once and therefore are set free continuously. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 2 "Ehud" to "Electroscope" 2011-01-29T03:00:23.777Z These results are consistent with the formation of a nondissociative bicarbonate intermediate on the zinc oxide support, contrasting with a CO dissociation mechanism on iron oxide, where the adsorbed carbon reacts with surface hydroxyls. Editors' Choice 2011-01-13T19:25:02.660Z The scientists are not saying that hydroxyl levels never vary, but that over a decade, at least, that variability appeared to be small. Green: A Steady Dose of Atmospheric Detergent 2011-01-06T22:19:43Z Carbon-14 in carbon monoxide is produced in the atmosphere by cosmic rays at a known rate, and is almost entirely removed by hydroxyl. Antarctic scientists begin hunt for sky’s ‘detergent’ 2018-11-19T05:00:00Z “To create this hydroxyl radical, you need sunlight,” he explains. Idling Jets Pollute More Than Thought 2011-05-11T15:10:00Z At the electrodes, however, the small quantity of hydrogen and hydroxyl ions from the water are liberated first in cases where the ions of the salt have a higher decomposition voltage. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 2 "Ehud" to "Electroscope" 2011-01-29T03:00:23.777Z However, the concentration of atmospheric hydroxyl radicals is extremely difficult to measure, so it must be inferred from measurements of the abundance of other species, like methyl chloroform. This Week in Science 2011-01-06T19:25:00.633Z Starting with elementary physical principles, the computers kept stubbornly suggesting that the levels of hydroxyl should be relatively steady. Green: A Steady Dose of Atmospheric Detergent 2011-01-06T22:19:43Z In the atmosphere gas-phase molecules emitted by plants are attacked by very specific molecules such as ozone or hydroxyl radicals that then change the chemical structure of the organic emissions by adding oxygen atoms. 'Archeologists of the Air' Isolate Pristine Aerosol Particles in the Amazon 2010-09-17T14:40:00Z Bases may be considered as salts with the hydroxyl group, OH, replacing the acid radical. The Mechanism of Life Thus the hydroxyl mentioned above decomposes into water and oxygen, and the chlorine produced by the electrolysis of a chloride may attack the metal of the anode. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 2 "Ehud" to "Electroscope" 2011-01-29T03:00:23.777Z In the solution, therefore, there is now an excess of hydroxyl ions; consequently it has an alkaline reaction and the litmus turns blue. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 2 "Bohemia" to "Borgia, Francis" The results, to be published on Friday in the journal Science, show much less variability in hydroxyl levels than previous studies. Green: A Steady Dose of Atmospheric Detergent 2011-01-06T22:19:43Z When the glucosides are hydrolyzed, they yield glucose and the hydroxyl compound of the radical with which it is united. The Chemistry of Plant Life The greater the concentration of the hydroxyl ions, i.e. the greater the dissociation, the stronger is the base. The Mechanism of Life This water-residue is known to chemists as “hydroxyl”—it is water less one atom of hydrogen. Coal and What We Get from It The meta-nitro-compound, which is precipitated last, is then reduced, and the amino group so formed is replaced by the hydroxyl group by means of the Sandmeyer reaction. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 3 "Capefigue" to "Carneades" Unfortunately, the most important greenhouse gas, carbon dioxide, is not one of those broken down by the hydroxyl radical. Green: A Steady Dose of Atmospheric Detergent 2011-01-06T22:19:43Z The substitution of a hydrogen atom by the hydroxyl group generally occasions a rise in boiling-point at about 100�. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" The basic character of a solution is determined by the presence of the hydroxyl radical OH-. The Mechanism of Life Similarly, the replacement of hydrogen by a water-residue, hydroxyl, gives rise to a phenol. Coal and What We Get from It The hydrogen of the hydroxyl group in phenol can be replaced by metals, by alkyl groups and by acid radicals. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 3 "Capefigue" to "Carneades" One-third of which is of benzenoid type The lignone contains but little hydroxyl. Researches on Cellulose 1895-1900 The nitro group behaves very similarly to the hydroxyl group. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" Recent work, however, has shown the existence of several so-called mixed glycerides, in which the hydroxyls of the same molecule of glycerol are displaced by two or sometimes three different acid radicles. The Handbook of Soap Manufacture Resorcinol is a phenolic derivative of benzene containing two hydroxyl groups; it is therefore related to phenol in the same way that diamidobenzene is related to aniline or phthalic acid to benzoic acid. Coal and What We Get from It It differs from cellulose in containing free carboxyl, CO, groups, while its hydroxyl groups, HO, are much more active in their chemical reactions. The Dyeing of Cotton Fabrics A Practical Handbook for the Dyer and Student The celluloses are in condensed hydroxyl union with the lignone, but the combination occurs by complexes of relatively large molecular weight. Researches on Cellulose 1895-1900 The amino group is more powerful than the hydroxyl, and the substituted amino group more powerful still; the repeated substitution of hydroxyl groups sometimes causes an intensification and sometimes a diminution of colour. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" Water forms an appreciable number of hydrogen and hydroxyl ions, and very weak bases such as bismuth hydroxide are dissociated to but a very slight extent. An Elementary Study of Chemistry These contain the group, or radical OH, hydroxyl, once or oftener. The Dyeing of Woollen Fabrics It is best detected in acid solutions by the deep brown or iodine colour developed on adding hydroxyl. A Text-book of Assaying: For the Use of Those Connected with Mines. Now in these triacid salts we can remove some of the acid groups and substitute the elements of water, OH, or hydroxyl, as it is called, for them. The Chemistry of Hat Manufacturing Lectures Delivered Before the Hat Manufacturers' Association The hydroxyl group also resembles the methyl group in its morphotropic effects, producing, in many cases, no change in symmetry but a dimensional increase in one direction. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" When a base dissolves in water the hydroxyl groups form the anions, while the metallic element forms the cations. An Elementary Study of Chemistry So also hydrogen would tend to take a position as near as possible to hydroxyl and to carboxyl, while hydroxyl would avoid hydroxyl, and carboxyl would avoid carboxyl. Scientific American Supplement, No. 633, February 18, 1888 The alkaline, or soapy taste, is the perception of hydroxyl radicles charged with negative electricity. Creative Chemistry Descriptive of Recent Achievements in the Chemical Industries They are regarded as formed from nitric acid by the replacement of hydroxyl by benzene radicals. Nitro-Explosives: A Practical Treatise By transformations of the carbonyl group, and at the same time of the hydroxyl group, many interesting types of nitrogen compounds may be correlated. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" It has the formula OH and is called the hydroxyl ion. An Elementary Study of Chemistry The hydrogen in the hydroxyl group, as is known, may be substituted by an alkyl group. Scientific American Supplement No. 822, October 3, 1891 Morphine, C17H19NO3, is a tertiary amine, and appears to contain a hydroxyl group like phenols, to which class of bodies it has some analogies, as is shown in its reaction with ferric chloride. Scientific American Supplement, No. 415, December 15, 1883 If, for example, a substance contains alkyl or hydroxyl groups, large quantities of the para compound are obtained, and very little of the ortho. Nitro-Explosives: A Practical Treatise ALCOHOLS, in organic chemistry, a class of compounds which may be considered as derived from hydrocarbons by the replacement of one or more hydrogen atoms by hydroxyl groups. The Project Gutenberg Encyclopedia Volume 1 of 28 Since all bases produce hydroxyl anions, while the cations of each are different, the properties which all bases have in common when in solution must be due to the hydroxyl ions. An Elementary Study of Chemistry This would then lead to curious conclusions concerning the hydroxyl group. Scientific American Supplement No. 822, October 3, 1891 The commonest radical is the negative OH, called hydroxyl, from hydrogen- oxygen. An Introduction to Chemical Science But since water is almost entirely undissociated, equilibrium can only be reached when there are very few hydroxyl or hydrogen ions present. An Elementary Study of Chemistry Sir Edward Frankland showed how it could be derived from, and converted into, ethane; and thus determined it to be ethane in which one hydrogen atom was repiaced by a hydroxyl group. The Project Gutenberg Encyclopedia Volume 1 of 28 There can therefore be neither hydrogen nor hydroxyl ions present in the solution. An Elementary Study of Chemistry For instance, an alkyl may be substituted for the hydroxyl hydrogen in an alcohol molecule, when an ether results. Scientific American Supplement No. 822, October 3, 1891 DEFINITION: A base is a substance which produces hydroxyl ions when dissolved in water or other dissociating liquids. An Elementary Study of Chemistry The solution of ammonia in water is found to have strong basic properties and therefore contains hydroxyl ions. An Elementary Study of Chemistry Alcohols are classified on two distinct principles, one depending upon the number of hydroxyl groups present, the other on the nature of the remaining groups attached to the carbon atom which carries the hydroxyl group. The Project Gutenberg Encyclopedia Volume 1 of 28 Thus, in the general reaction between an acid and a base, the essential action is between the univalent hydrogen ion and the univalent hydroxyl ion. An Elementary Study of Chemistry They are distinguished from each other by prefixing the name of the element which is in combination with the hydroxyl group. An Elementary Study of Chemistry A solution of potassium cyanide turns red litmus blue, and must therefore contain hydroxyl ions. An Elementary Study of Chemistry Sodium or potassium dissolves in them with the formation of alcoholates, the hydrogen of the hydroxyl group being replaced by the metal. The Project Gutenberg Encyclopedia Volume 1 of 28 |
| 随便看 |
英语例句辞典收录了117811条英语例句在线翻译词条，基本涵盖了全部常用单词及词组的例句翻译及用法，是英语学习的有利工具。