- 1.
[连接的从句常用should或动词原形] 以免，免得，唯恐 -
• Be careful lest you fail. 你要小心，以免失败。 -
• They spoke in whispers lest they should be heard. 他们低声耳语，唯恐被人听见。 - 2.
[用在 be afraid, fear, worry, danger等词后，仅起连接作用，相当于that] -
• We were afraid lest he should arrive too late. 我们担心他会到得太迟。 -
• There was danger lest the plan be known. 恐怕这个计划有泄露的危险。
用法说明
lest, in case, in case of
lest较正式，其义为“恐怕”、“惟恐”或“担心”。作“担心”解时，常与fear, be afraid of, be anxious等连用，例如：
He ran away lest he (should)be caught.他怕被抓，因而逃走了。
I was afraid lest she might be offended.我担心把她给得罪了。
in case意思为“以免”。in case of表示“假如某事发生”。试比较：
I don't let him climb trees in case he tears his trousers.我不让他爬树，以免撕破裤子。
In case of fire, ring the alarm bell.如果失火，就按警铃。