If they ______, our plan will fall flat.a. are co-operating b. had not co-operated c. won’t co-operate d. didn’t co-operate
---- It is generally believed that teaching is __________it is a science.
----Three students came late to school this morning, Tom and Jack_______.
----Drinking is harmful_______our health.
----Must I finish the jod at seven o’clock? ----No, you___________
---- The reason why he has been such a success is ________he had lost his money.