need 表示“需要”或“必须”,作情态动词时,仅用于否定句或疑问句中.
在肯定句中一般用must,have to,ought to或should 代替.例如:
You needn't come so early.
Need I finish the work today?--Yes,you must.
注意:needn't have done“表示本来不必做某事而实际上做了某事”.例如:You needn't have waited for me.
“should have done”表示应该做到而实际上没有做到.
You should have started earlier.
“ought to have done”表示过去应做某事而实际未做.
You ought to have helped him (but you didn't)
切记:need作情态动词时仅用于否定句或疑问句中在肯定句中一般用must,have to,ought to或should代替
[返回
猜你喜欢
- 1与“warm”同一种类型的单词除了cold、cool和hot之外还有哪些单词?
- 2已知f(x)=2x3-6x2+m(m为常数)在[-2,2]上有最大值3,那么此函数在[-2,2]上的最小值是( ) A.-37 B.-29 C.-5 D.以上都不对
- 3I met Lilei__hospital last sunday.he wad ill__hospital then Ain the,in the Bin the,in
- 4PH 计上所用的指示电极是a甘汞电极 b玻璃电极 c氯化银 d 铂电极
- 5Mr.and Mrs.smith often( )their children to zhongshan park
- 6电功的单位一焦耳等不等于我们用手做功的一焦耳
- 7250ML牛奶等于几斤
- 8阅读理解:《鹰之歌》高尔基的所有答案
- 9某患者需要补充0.05摩尔的钠离子,需要生理盐水多少毫升,过程是什么.
- 10y的3次方-3y的平方+y