lest

lest
lest 惟恐；以免；担心；以防万一
用作连词 (conj.)
They spoke in whispers lest they should be heard.
他们低声说话，唯恐被别人听见。
He took a flashlight lest it should get dark before he returned.
为了预防回来以前天就黑了，所以他带着手电筒。
I got up early lest I should miss the train.
我早起以免错过了火车。
We talked in a low voice lest we should wake the baby up.
我们小声说话以免吵醒婴儿。
I was afraid lest the new car should be stolen.
我担心新汽车会被偷走。