Working hard is not a _______ of great success, but it is among the essential requirements.
| A．mark | B．guarantee | C．key | D．signal |
— We shall take the conditions into careful account ____ you have attached to this contract.
— Thanks. Hope for further cooperation.
| A．as | B．which | C．where | D．what |
— I’ll be able to come to see your performance at 8:30 tomorrow evening.
— I’m sorry, by then my performance ____ and I ____reporters in the meeting room.
| A．will be ended; will meet | B．is to end; will meet |
| C．will have ended; will be meeting | D．will end; am going to meet |
The split between humans and living apes is thought by some scholars ____ 15 to 20 million years ago.
| A．to occur | B．occurring | C．to have occurred | D．having occurred |
— Linda hasn’t shown up yet.
— It’s strange. She ____.
| A．could | B．might | C．must have | D．should have |
David applied for the position three times ____ he finally got it.
| A．until | B．when | C．before | D．after |