Question

--- What has made him upset recently?
--- __________ alone to face a troublesome case．

A．Left

B．Being left

C．Having left

D．To leave

Answer 1

B 

试题分析：句意：--什么使他最近不安？--被单独留下面对棘手的情况。因为问句是what…?对主语提问，所以回答的是主语的内容，用动名词做主语，he和left是被动关系，用动名词的被动做主语，选B。