情态动词考点总结:
dare作情态动词和行为动词的用法: dare作情态动词主要用在否定句和疑问句中,其中否定式是"dare not + 动词原形"表示"不敢,竟敢"。 例如:She dare not speak in public. 她不敢在公众面前讲话。
How dare you do such a thing? 你怎敢做这样的事? dare作为行为动词时,肯定是为"dare to do sth.", to可以省略;其否定式为"don't dare (to) do/doesn't dare (to) do/didn't dare (to) do"。
She dares (to) swim in that river. 她敢再那条河里游泳。
I don't dare (to) speak of it. 我不敢说那件事。
need作情态动词,常用于否定句和疑问句中,其否定式为"needn't + 动词原形"。 例如:You needn't do anything here. 你在这里什么也不要做。
You needn't go if you don't want to. 你不想去就不必去。
You needn't do it at once, need you? 你不必马上做,是吗?
need作行为动词时,其否定式为"don't need to do…", 后面接动词不定式,表示主动;接动名词表示被动。 例如:You don't need to do it yourself. 你不必亲自做这件事。
I need to tell them the news. 我需要告诉他们这个消息。