1. drift off就是“慢慢地睡去、进入梦乡”的意思。

It was only when he finally drifted off to sleep that the headaches eased.

当他最终慢慢睡着时，头疼才减轻了。

2. right as rain

rain有着“吉祥、好运”的含义，中文中也有及时雨的说法。

right as rain本来指“非常健康；情况良好”，这里也有“特别合适”的意思。

You just need a good night's sleep, and then you'll be right as rain again.

你只要好好睡一晚上觉就会完全恢复了。

3. life 表示“活力，热情”，pump是“打气”的意思，注入活力就是pump life into sth，很形象吧！

She's so full of life.

她充满了活力。

pump sb up的意思是“给(轮胎等)打气；使鼓起勇气”。

He was offering them advice and trying to pump them up.

他给他们提建议，努力给他们打气。