They themselves had had a similar experience.

　　他們本身就曾有過類似的經(jīng)歷。

　　These cells are able to reduplicate themselves.

　　這些細(xì)胞能自我復(fù)制。

　　Some animals roll themselves into a ball for protection.

　　有些動物蜷縮成一團以保護自己。