It is hard to imagine what progress they _____ in the past few months.[ ]

.—I’ll ask the teacher about theattributive clause. I’m very puzzled about it —That’s just ____ most of our classmateshave doubt.

–I heard The Wonder girls would sing at the HongBo Theater. –Where did you ____?

My father likes jogging the Moon River for half an hour every morning.

Excuse me, I was told I could find Professor Li here.— And you ______Anything I can do for you?