同学你好，该知识点来自沪江网校《新概念英语2、3、4册连读【双11专享班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
I was afraid to open the door lest he should follow me. 我不敢开门，怕他跟着我。
这里lest的意思是“you do it to try to prevent the unpleasant thing from happening.”做这件事以阻止不好的事情发生，相当于so that he should not follow me 免得他跟着我，意思是相近的。
类似的比如
They spoke in whispers lest they should be heard.
他们低声耳语惟恐被人听见。

与least含义相同的词组还有：for fear that / in case
按正式程度：lest ＞ for fear that ＞ in case
We spoke in whispers for for fear (that) we might wake the baby. 我们轻声谈话, 以免吵醒婴儿.
We spoke in whispers for fear of waking the baby. 我们轻声谈话, 以免吵醒婴儿.

祝同学学习进步~