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 flashpght 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。

I feared lest I should be late again.
我唯恐自己再迟到。

I ran as fast as possible lest I should be too late.
我尽量快跑,免得迟到。

Be careful lest you (should) fall from the tree.
小心,不要从树上掉下来。

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”。

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 flashpght 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。

I feared lest I should be late again.
我唯恐自己再迟到。

I ran as fast as possible lest I should be too late.
我尽量快跑,免得迟到。

Be careful lest you (should) fall from the tree.
小心,不要从树上掉下来。

• for fear that以免
• perchance偶然
• in case万一，以防
• so as not to以便不, 以免...
• fear担心
• in在 ... 里
• that那
• if是否
• for为
• order顺序
• to对于
• avoid避免