Although he has failed many times, he keeps _____ hard to make his dream come true.A. working B. to work C. worked
I don’t know ______ with this problem. It’s too hard.
The notebook ___________ be John's .There is his name on it.
_____you go, ____you do in your school, You must obey the rules.
Tony didn't run ________.He was behind all the other runners.
He used to like playing________ piano,but now he likes playing _________ basketball.