题目

—Will you stay for lunch? —Sorry, ________ my brother is coming to see me. A.I mustn't  B.I can't C.I needn't  D.I won't 答案：B考查情态动词在一般疑问句答语中的用法。mustn't 意为“不允许、禁止”；can't指“客观上不能办到”；needn't指“不需要”；won't指“不会，不愿意”。本题易误选D项，I won't只考虑了将来时，而实际上，吃饭这件事根据后面的情况是办不到的。所以答案为I can'tHave you ever ________ (write) a letter to your parents?