David his friend’s invitation to the picnic in order to stay at home and study for the test.
A. expected B. refused C. received
You ________ wait for him. I’m not sure whether he’ll come back or not today.
| A．can’t | B．shouldn’t | C．mustn’t | D．needn’t |
—Why do you look so tired?
—Because we ________ for three hours without stopping.
| A．work | B．worked |
| C．have worked | D．were working |
We won’t start the meeting ________ the teacher arrives.
| A．though | B．until | C．while | D．and |
The workers are trying to ________ what’s wrong with the machine.
| A．look for | B．care for | C．find out | D．take out |
Internet is ________ used by people, especially by young people.
| A．deeply | B．widely | C．hardly | D．highly |