—What made Jack so upset?
— three tickets for the music concert.
A. Lost
B. Losing
C. Because of losing
D. Since
网友回答
A. Lost
(答案→)B. Losing
C. Because of losing
D. Since
解析：此题考查非谓语形式。具体考查的是识别动名词短语作句子主语的能力。上句问“什么使杰克这么不安？” 答句是个省略句，完整的句子应为“Losing three tickets for the music concert made Jack so upset.” 选项A是过去分词，不可作主语；选项C、D连接的部分只能作状语。因此只能用动名词losing短语作主语。