Steve said that if he _________ how it worked, he __________ me what to do.

A．knows; would tell                                       B．had known; would have told

C．knew; would have told                   D．had known; would tell

Steve said that if he ________ how it worked, he ________ me what to do．

1. A.
   knows; would tell
2. B.
   had known; would have told
3. C.
   knew; would have told
4. D.
   had known; would tell