--- What do you suppose made her worried?
--- a new cell phone.
A. Lose
B. Lost
C. Losing
D. Because of losing
网友回答
A. Lose
B. Lost
(答案→)C. Losing
D. Because of losing
解析：考查动名词做主语：句意：--你认为是什么让她担心的？-是失去了新的手机。这句话回答的是问题里面的what（主语），用动名词做主语，这句话是省略句，完整的是Losing a new cell phone made her worried.选C。