Scientists are convinced __________ the positive effect of laughter _________ physical and mental health.
| A．of; at | B．by; in |
| C．of; on | D．on; at |
When I got to the checkout counter, I realized I didn’t have enough money, so I kept ________ I really needed and left the rest．
| A．what | B．which | C．that | D．this |
Although it was not named ________ 1782, this kind of metal was used as early as 5300 BC．
A．in B．for C．until D．since
--Who is late for class again?
--________ you ask? Tim, of course．
| A．Can | B．Would | C．Could | D．Need |
--Shall I give you a ride to the Capital Airport?
--Thank you．________．
| A．If you like | B．It couldn’t be better |
| C．Of course, you can | D．It’s up to you |
--Kathy and her sister are so alike．
--Yeah, I can’t tell one from ________．
| A．another | B．other | C．the other | D．others |