问题

The importance of saving gas ______ be stressed too much. Automobiles use up some 70 billion gallons of gas a year.[ ]

A: mustn’t
B: cannot
C: shouldn’t
D: may not

正确答案是：

同类题型

The art show is___being a failure;itwas a great success.[ ]

______ — It’s 8:00 now. Time for class.

With so many people __________ in English every day, it will become more and more important to have a good ___________ of English.

She told us what she bought yesterday ________ afew apples and some clothing

________–He’s friendly and helpful. He often helps me with my homework.