Chemists are still working on more creative salt combinations that may one day more closely approximate table salt.

化学家仍在研究更有创意的盐的组合，有朝一日可能会更接近食盐。

In the late 19th century, ventilation techniques largely focused on negative pressure, which closely approximates natural breathing and provides an even distribution of air in the lungs.

十九世纪晚期的呼吸机技术主要为负压式呼吸，这一过程模拟了自然呼吸，并保证了肺部均匀的空气分布。

But it turns out if I were to plot 10,000 of the sample means here, I'm going to have something that, two things-- it's going to even more closely approximate a normal distribution.

但事实证明，如果我在这里绘制 10,000 个样本均值，我将得到一些东西，两件事 - 它会更接近正态分布。