Unless ___ to speak，you should remain silent at the conference．
| A．invited | B．inviting | C．being invited | D．having invited |
.
-----I’m terribly sorry to have put you through so much trouble.
-----________. I know you didn’t mean to.
| A．Forget it | B．No trouble |
| C．All right | D．You’re welcome |
.
It was ______ the 19th century_____ heat was considered to be a form of energy.
| A．not until; that | B．until; that |
| C．not until; when | D．until; when |
.
Don’t you think ti is unfair for about two thirds of the population to have no_____ to health care?
| A．access | B．basis | C．entrance | D．guarantee |
.
When Bill Gates decided to stop schooling and created Microsoft in 1975, he ______ law at Harvard University.
| A．studied | B．had studied | C．was studying | D．would study |
.
______ pressure the U.S. government put on the Chinese government, China would stick to its own policy of exchange rate.
| A．However | B．Wherever | C．Whoever | D．Whatever |