-Is Jack on duty today?
-It ____ be him. It’s his turn tomorrow.
| A．mustn’t | B．won’t | C．can’t | D．needn’t |
The passenger was very impolite to the conductor, ____ , of course , made things even worse.
| A．who | B．whom | C．which | D．what |
_____ was known to all , Willian had broken his promise ______ he would give us a rise.
| A．As; which | B．As; that | C．It; that | D．It ; which |
John knocked at the door for nearly five minutes____his wife opened it.
| A．when | B．before | C．until | D．as |
---The thread of my kite broke and it flew away.
---I told you it would easily break_____was the weakest.
| A．where | B．the place where | C．for it | D．where it |
They were surprised that a child could work out the problem____they themselves couldn't.
| A．once | B．while | C．then | D．if |