need的用法

need的用法

need作为动词，有两种理解，一是做情态动词，二是做行为动词。\x0d\x0a1）need作为情态动词时，一般不用于肯定句，只用于否定句/疑问句。\x0d\x0a其后直接加动词原形，没有时态/人称的变化。\x0d\x0a其否定句为在need后面直接加not，或使用缩写needn't.\x0d\x0a如：I needn't work hard.\x0d\x0a其疑问句必须把情态动词need提前，回答也一般借助于need.\x0d\x0a如：Need I help you?\x0d\x0a2）need作为行为动词时，可用于各种句子，有过去式needed和三单形式needs.\x0d\x0a其否定句必须借助于助动词don't/doesn't/didn't等变化。\x0d\x0a如：I don't need to work hard.\x0d\x0a其疑问句也必须借助于助动词do/does/did等变化。\x0d\x0a如：What do you need me to do?\x0d\x0a其结构一般有：\x0d\x0aneed sb/sth 如：I need you. I need your help.\x0d\x0aneed to do sth 如：I need to work harder.\x0d\x0aneed sb to do sth 如：I need you to help me.\x0d\x0aneed doing = need to be done 如：My watch needs repairing. = My watch needs to be repaired