He‘sworkinghard_____.
B
for fear (that)“惟恐，以免 ”，引导的从句用虚拟语气 should+动词原形， should 可省略。 lest 意思及用法类似。
He‘s working hard_____.
He‘sworkinghard_____.
Hedidn‘tseemtomind_____themusicwhilehewasstudying.
_____you understand this rule ，you‘ll have no difficulty in dealing with such problems.