Scientists are convinced _____the positive effect of laughter _____physical and mental health．
| A．of ;at | B．by; in | C．of ; on | D．on ;at |
The homeless boy was hungry and cold, ______for attention.
| A．starving | B．making | C．leaving | D．looking |
. I’ll pay him_______for the trick he played______me.
| A．off; with | B．back; to | C．off; on | D．back; on |
She could be with her friend right now______at him.
| A．laugh | B．laughed | C．laughing | D．being laughed |
Let’s go to______ cinema. That’ll take your mind off the problem for
______while
| A．the; the | B．the; a | C．a; the | D．a ; a |
You ______be tired. You’ve only been working for an hour.
| A．must not | B．won’t | C．can’t | D．may not |