如题所述
need既可以作情态动词,也可以作实义动词,还可以作名词,各自的用法不同。
一、need作情态动词时,表“必须,必要”,其用法为:
后直接跟动词原形,need+do,否定needn't+do。
need无人称、数的变化,第三人称单数不加s,也没有非谓语形式。
注意:need用作情态动词时,常用语否定句和疑问句中。
must引导的一般疑问句的否定回答,必须使用needn't,肯定回答用must。
二、need作实义动词的用法:
need+something(名词)需要某物
need to do something 需要做某事
need doing=need to be done 需要……
need somebody to do something 需要某人做某事
Need作为情态动词、实义动词以及名词,在英语中有不同的用法和含义。
作为情态动词时,need主要用于疑问句、否定句、条件句、含否定意义的从句及动词不定式结构中。它没有第三人称单数形式、非谓语形式和词形变化,并且后接动词原形。例如:
Need I remind you of that?
You need not worry about this.
If she needs help, let me know.
I felt that I needed to leave.
You need only to do it once.
当need用作实义动词时,它有各种时态和人称的变化,并可以后接动名词、不定式或名词作宾语。例如:
He needs to finish his homework before going out.
She needs a new dress for the party.
They needed to consult an expert on the matter.
作为名词使用时,need指的是需要或必要性。例如:
There is no need to hurry.
The refugees are in dire need of food and shelter.
在实际应用中,need还可以与have连用构成短语have need of,表示需要某物或某人。例如:
We have need of your help.
另外,need可以与for搭配使用,形成need for something的结构,表达对某物的需求。例如:
There is a growing need for qualified teachers.
在使用need时,需要注意其作为情态动词和实义动词的不同语法特点,以确保句子结构的准确性。