语法精讲
情态动词had better, should及 ought to的用法
(1)had better 最好
①加动词原形
You’d better get some sleep. 你最好睡一会儿。
I’d better not disturb him. 我最好不打扰他了。
②后接be doing sth. 表示最好立即做某事
I think I’d better be going.我想我最好立刻走。
③祈使句中had省略
Better not wait for them. 最好不等他们。
④反义疑问句用had
You’d better put away your socks, hadn’t you? 你最好把你袜子收拾好，难道不行吗？
You had better not follow her, had you？你最好不要跟她，不是吗？
(2)should 与ought to 应该
①ought to 的口气比should 稍重一些，更侧重于某件事责任、义务上该做的事情。should表示某件事宜于做。下列句子两个词不宜换用：
You are his father. You ought to take care of him.你是他的父亲，就应该照顾他。
We should not use too many big words in our everyday speech.
我们不应该说太多的大话在我们的日常讲话中。
②ought to 的句式变化
否定句：You ought not =(oughtn’t) to write so carelessly.你不该写得这样粗心。
疑问句：Ought we to give him a chance to try？我们该给他机会试一试?
③与完成时连用
should/ought to have done sth.本应该做……(而实际没做)
We ought to have finished our homework on time.我们本应该按时完成作业。
shouldn’t/oughtn’t to have done sth.本不应该做……(而实际做了)
They oughtn’t to have come back so late.他们本不该回来这样晚。