While listening in class, you should concentrate ____ your teacher.
A. at B. to C. for D. on
Schools don’t allow ______ answers in the exam.
A. copy B. to copy
C. copying D. copied
Thomas Edison is known _____inventions______ a great inventor.
A. to, as B. for , as
C. as, to D. to, for
An accident______ on this road last week.
A. has been happened B. was happened
C. is happened D. happened
Tom is often made ______for twelve hours a day by the boss.
A. work B. working
C. to work D. to be working
I don’ t mind _____the door.
A. you open B. your open
C. your opening D. yours opening
