题目内容：

they do well in the exam.A.can be able to B.be able to C.can able to D.are able to 选哪个?

优质解答

正确答案：选D
即：They are able to do well in the exam.
翻译：他们在考试中能答得很好.
解析：be able to 能够的意思,有人称和时态的变化.
有不明白的请继续追问,