请看这道题，如何回答？

―What made you so worried?

―__________

A. Because I lost my wallet.              B. As I lost my wallet.

C. Losing my wallet.                         D. Lost my wallet.

此题应选C。容易误选A。

分析：由于问句中的疑问词what在句中用作主语，所以其相应的答语也应是能用作主语的成分。答案A，B错误，因为它们是原因状语; 答案D错误，因为过去分词不用作主语。

选项C正确，因为动名词可用作主语。答句其实是一个省略句，补完整为：Losing my wallet made me so worried. 在回答特殊疑问句时，要特别注意其疑问词的含义以及它在句中的句法功能；反过来，要是根据答语选择疑问词，也要注意其对应关系。如：

1. ―_________ does he come to see you?

―Once a week.

A. How long             B. How often              C. How soon               D. How much

2. ―How long has he lived here?

―________ he was a child.

A. After                    B. Before                   C. Since                      D. When

3. ―_________ is the capital of China?

―Beijing is.

A. Where                  B. What                     C. Which                     D. How

答案：1. B 2. C 3. B