The teacher ____________his students to leave the classroom as soon as possible .
| A．required | B．suggested | C．demanded | D．desired |
So far no life has been found outside the earth, but while some scientists are actively searching for living things in outer space, others firmly believe there ____ .
| A．mustn’t be | B．may not be | C．can’t be | D．won’t be |
I have never seen the word ______ that way before.
| A．to use | B．used | C．using | D．to be used |
I appreciated ____ the opportunity to study abroad two years ago.
| A．having been given | B．having given |
| C．to have been given | D．to be given |
The International Day against Drugs, aimed at warning people to keep away from drugs， _________ on June 26th every year．
| A．taking place | B．takes place | C．took place | D．taken place |
. Progress so far has been very good. _______, we are sure that the project will be completed on time.
| A．However | B．Otherwise | C．Therefore | D．Besides |