lest

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]

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。

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。