—What made Jack so upset?— three tickets for the music concert.A. Lost B. LosingC. Becau

问题补充：

—What made Jack so upset?

— three tickets for the music concert.

A. Lost

B. Losing

C. Because of losing

D. Since

答案：

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。