A millstone is a very large, heavy stone used for grinding things such as grain or corn.

磨石是一种非常大、很重的石头，被用来碾磨谷物或玉米等东西。

The speed of the whirling air makes quite small things such as grains of sand into dangerous weapons.

旋转的空气的速度使很小的东西如沙粒变成危险的武器。

The Organization for Economic Cooperation and Development sees the average prices of products classified as essential such as grains, vegetable oils, and dairy products rising for the next decade.

经济合作与发展组织认为，谷物、植物油和奶制品这些基本食品的平均价格在未来十年都将持续上涨。