Question

– I rang you at about ten o’clock, but there was no reply.
– Oh, that was probably ________ I was seeing the doctor

1. A.
   when
2. B.
   why
3. C.
   what
4. D.
   that

Answer 1

A
考查表语从句：表语从句部分I was seeing the doctor.不缺主宾表， 说明不能用what，根据句意：--10点我打电话给你，但没人接。--那可能是我去看医生的时候。选A。