lest /lɛst/ CET4 TEM4

• 1. 

  CONJ If you do something lest something unpleasant should happen, you do it to try to prevent the unpleasant thing from happening. 以防 [正式]

  例：

  I was afraid to open the door lest he should follow me.

  我当时害怕打开那个门惟恐他跟踪我。

  例：

  And, lest we forget, Einstein wrote his most influential papers while working as a clerk.

  而且，为了不使我们忘记，爱因斯坦在做小职员的时候写了他最有影响的论文。