I don’t know when he _________ tomorrow. If he _________, I’ll let you know.

I don’t know when he _________ tomorrow. If he _________, I’ll let you know.

1. A.
   comes, comes
2. B.
   will come, comes
3. C.
   comes, will come
4. D.
   came, will come

I don’t know when he _________ tomorrow. If he _________, I’ll let you know.

-I don't know ________ he will come tomorrow．

-Don't worry．________ he comes, I'll let you know．

1. A.
   whether, If
2. B.
   if, Whether
3. C.
   when, Whether
4. D.
   that, If