— How much are the two pairs of trousers? — They are not expensive. I think one hundred dollars ______ enough.

 Mary is one of the girls who _____ often late for school.

The number of students in our school         five hundred.

The city government is planning to build a factory to deal with the industry waste，but when and where to build it________.

When the head teacher announced his plan for an autumn outing, the _______ of the students in the class _____for it.