— How about buying an iPhone 4s for your mother’s birthday?— Oh, maybe it’s too expensive, Dad. Do you know _______?
—________ Tom and his mother often watch tennis games on TV? —Yes, they ________.
Simon’s father is talking _______the teacher ______his son’s English.
Mike is good at _________. He can ________ well.
Jane likes ________ and she _________every week.
There is ________“s” and ________“f”in the word “useful” .