问题描述：
Let them not swim in the river为什么要用not不用do not
He lives in Shanghai.为什么不能加写成He is lives in Shanghai.
My aunt lives in the United States.为什么要用lives in
He lives in Shanghai.为什么不能加写成He is lives in Shanghai.
My aunt lives in the United States.为什么要用lives in
问题解答：
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