A study shows the students who are engaged in after-school activities are happier than _________who are not.
ones
those
these
them
I didn’t know that he was a cheat, or else I ________________ him.
________ the present unemployment continue, the society would face a more troublesome situation.
I forget where I learned the saying, or I _____ it to you now.
—Do you think George has passed the driving test?—No. If so, he ______ his car to our college yesterday.
— Did you see it with your own eyes, Mike? — Yes. Otherwise I _______you about it.