---What ______ the number of students in your school?
---About two thousand. A number of them _____ from the countryside.
A. is, are B. is, is C. are, is D. are, are
Ben is a foreign teacher. So far, he ______ in our school for five years.
A. was teaching B. has taught
C. will teach D. taught
To protect trees, we shouldn’t use paper towels ______napkins.
A. or B. and C. but D. with
I haven’t _______ my parents for a long time. I miss them very much.
A. hear of B. heard of
C. hear about D. heard from
You can save electricity by _______ the lights when you leave a room.
A. turn up B. turning on
C. turn off D. turning off
People are _____ litter ______the river.
A. throw, to B. throw, into
C. throwing, for D. throwing, into
