need 用法 need可当“情态动词”或“实意动词”来用.那么,什么时候当“情态动词

need 用法 need可当“情态动词”或“实意动词”来用.那么,什么时候当“情态动词
need 用法 need可当“情态动词”或“实意动词”来用.那么,什么时候当“情态动词”来用,什么时候当“实意动词”来用呢?如：(D)You___to the meeting today if you have something important to do.A.needn' to come B.don't need come C.don't need coming D.needn't come 此题为何选D不选A?