CONJ-SUBORD
唯恐;免得
If you do something lest something unpleasant should happen, you do it to try to prevent the unpleasant thing from happening.
例句
I was afraid to open the door lest he should follow me...
我不敢开门,唯恐他还跟着我。
The president has gone along with the hardliners lest they be tempted to oust him...
总统同意了强硬派的意见,以免他们产生赶他下台的念头。