Mr Smith was really helpful when you were in financial difficulty during those years— Definitely I can never appreciate his kindness ________

Mary wanted to travel around the world all by herself, but her parents did not _______ her to do so.

What’s wrong with your ipad2? The sound ____is not clear.—Yes. It has been broken for some time. [ ]

Mr Wang teaches ______ English. He is friendly to ______.

Come and see me whenever ____.