题目内容：

The nervous boy didn't know ___A whom to listen B whom he listens to C whom he would listen
D whom to listen to

优质解答

答案：D解释：1. B中此句的时态为一般现在时,和主句时态不对应,排除；C中的whom不能直接做listen的宾语,如果加上to就对了.2. AD是所谓的“疑问词 + 不定式”结构,它相当于一个名词短语,在此句中可以做know的宾语.如...