conj.惟恐；以免；担心

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。

lest是从属连词,意为“以免,唯恐”。常用于引导目的状语从句表示否定,只用于书面语。lest在表示“惊恐”“忧虑”的动词后引导宾语从句,相当于that。

lest所引导的从句中谓语动词要用虚拟式,即“(should+)动词原形”。