25.大脑细胞储存记忆的机理并不为人明白。

25. The mechanism by which brain cells store memories is not clearly understood.

24.大多数物质遇冷收缩，所以他们的密度在固态时高于液态。

24. Most substance contract when they freeze so that the density of a substance's solid is higher than the density of its liquid.

23.在大量的实验中，某一事件发生的几率等于它不发生的几率。

23. Over a very large number of trials, the probability of an event's occurring is equal to the probability that it will not occur.

22.一个国家的主要食物是什么，大体取决于什么作物在其天气和土壤条件下生长得最好。

22. The chief foods eaten in any country depend largely on what grows best in its climate and soil.

21.用怪罪别人的办法来解决问题通常被称为寻找替罪羊。

21. Eliminating problems by transferring the blame to others is often called scape-goating.