need的否定形式可以是needneedtodosth为啥在否定形式时不可以呢?needdoingsth在否定形式时
怎样才能判断needtodosth与needdoingsth?
例题:1.Hedoesnotneed________(do)toomuchhomework.
2.Youneedtoeatmorevegetbables.(改为否定句