--I don't think we have met before.
--Yes, once at a party, but we___________.
| A．weren't introduced | B．didn't introduce |
| C．haven't introduced | D．were not introducing |
Everyone knows, perhaps except you, _______ your girl-friend is a cheat.
| A．who | B．which |
| C．that | D．what |
Someone is ringing the doorbell. Go and see ______.
| A．who is he | B．who he is |
| C．who is it | D．who it is |
It was ten o’clock _____ he came back home.
| A．when | B．that |
| C．since | D．after |
“Where _______ go to work？” “Where _______ go to work is not known.”
| A．we shall, we shall | B．shall we, shall we |
| C．shall we, we shall | D．we shall, shall we |
It was when she was about to go to bed ______ the telephone rang.
| A．since | B．as | C．that | D．then |