Even the most apathetic students are beginning to sit up and listen.

即使最漠不关心的学生都开始坐直身子听了。

She started to sit up, grimaced, and sank back weakly against the pillow.

她开始坐起来，痛苦地皱着脸，又虚弱地靠回到枕头上。

His back is weak because he won't try to sit up.

他的背很虚弱，因为他不愿试着坐起来。

"Colin's so afraid of it himself that he won't sit up," said Mary.

“科林自己也很害怕，他都不敢坐起来。”玛丽说。