Question

---When ________ again?

---When he ________, I’ll let you know．

1. A.
   he comes; comes
2. B.
   will he come; will come
3. C.
   he comes; will come
4. D.
   will he come; comes

Answer 1

D
when引导的时间状语从句用一般时代替将来时，he为第三人称单数，故第二空格应为comes，根据第二句句意可以推断第一句应为将来时。