—I have worked hard at math, but it seems that I haven’t made any progress. —Keep on _____ at it, and you will be successful. A. work B. working C. to work
He decided to study hard__________ catch up with others.
This dress still looks pretty on you, _______ it is out of style.
—Mike, could you tell me if Mary to my party tomorrow? —I think she will if she time.
Jim came into the room ______ Millie sat down on the chair last night.
---Could you tell me_________? ---Sorry, I have no idea, either. You can ask the policeman over there.