Students ______ remain in their seats until all the exam papers have been collected.
| A．must | B．shall | C．may | D．can |
The time and effort he has devoted during the past few years____ trees in that remote area is now considered to be of great value．
| A．to plan | B．to planting | C．plant | D．planting |
After five hours’ drive, they reached ____ they thought was the place they had been dreaming of.
| A．what | B．that | C．which | D．where |
— People should spare no efforts to protect the environment.
— ________. Air pollution does harm to our health.
| A．All right | B．Take it easy | C．Go ahead | D．Exactly |
The _______ of students in our class are from the country; only five are from cities.
| A． most | B． majority | C． minority | D．mostly |
What would you give her _______ the painting she collected?
| A． in place of | B． in favour of | C． on account of | D．in exchange for |