Professor Johnson is said _____ some significant advance in his research in the past year.
| A．having made | B．making | C．to have made | D．to make |
—Why are you standing here?
—I’m waiting for Shirley. She will be back _____.
| A．gradually | B．originally | C．shortly | D．abruptly |
By the year 2020 scientists _____ a lot of research on AIDS.
| A．had done | B．do | C．are doing | D．will have done |
The former manager of the company was said _____ in an organized crime.
| A．to be involved | B．to involve |
| C．to have involved | D．to have been involved |
_____ is commonly believed that the play was written by Shakespeare.
| A．It | B．That | C．What | D．As |
I will buy this type of car _____ the price is brought down to under 10,000 dollars.
| A．even if | B．provided that | C．unless | D．whether |