用于表示“需要,必要”之意。做情态动词时,仅用于否定句和疑问句,只有现在时,过去式要用needn't have,疑问式用need+人称?,否定式用need not(即needn't), 1.—need we leave soon? —yes, you must.(no, you needn't) 2.you needn't have hurried. (=it was not necessary for you to hurry,but you did).你当时不必这么匆忙。 3.he needs to see a doctor.(need to do)