好多人都会被情态动词搞混，can和Could，may和might，should和must，什么时候用哪个，我们今天来捋一捋，我来为大家讲解一下关于情态动词的should的用法?跟着小编一起来看一看吧!
情态动词的should的用法
好多人都会被情态动词搞混，can和Could，may和might，should和must，什么时候用哪个，我们今天来捋一捋。
Might & May我们用might表示可能会发生的事。比如说：
Where are you going for your holidays?
--I'm not sure. I might go to New York.
我可能会去纽约。
It might rain.
可能会下雨。
may和might有什么区别呢？其实两者都可以同样使用，表示不确定，可能会发生的事。比如：
I might go to the cinema this evening.
=I may go to the cinema this evening.
我可能今晚会去电影院。
Sue might not come to the party tonight.
=Sue may not come to the party tonight.
Sue今晚可能不会来参加派对了。
Can & Could我们用can来表示“知道怎么做...”或者“对某人来说，...是可操作的”。
I can play guitar, but I can't play piano.
我会弹吉它，但是我不会弹钢琴。
Can you swim?
--Yes, but I'm not a very good swimmer.
如果是在过去时态里，我们就用could/ couldn't。
When I was young, I could run very fast.
当我年轻的时候，我可以跑得很快。
Before Anna came to England, she couldn't understand much English, but she can understand everything now.
Anna去英国前不懂太多英语，但是现在她能懂所有事。
Must & Had to & Have to我们用must来表示“必须要做的事情”。
It's a fantastic film, you must see it.
这是部很好的电影，你必须看一看。
We must go to the bank today, We haven't got any money.
今天我们必须去趟银行了，我们没有钱了。
在过去时态里，我们用had to...来表示。
We had to go to the bank yesterday, because we haven't got any money.
我们昨天必须去银行，因为那时候我们已经没有钱了。
I had to walk home last night.
昨晚我不得不走路回家。
有小伙伴就会说了，如果按时态来算，had to 是过去时态，那现在时态里，不应该是have to 吗？
对的，在现在时态里，must在某种情况下是可以和 have to 同等替换使用的。
当must 和 have to 都表示“你觉得是必须的，你给出你的个人意见”时，两者可互换使用。比如：
It's a fantastic film, you must see it.
=It's a fantastic film, you have to see it.
这部电影很精彩，你必须去看一看/你真的得去看一看。
当“你不是在给出你的个人意见时”，就只能用have to。比如：
Jill won't be here this afternoon, she has to go to the doctor.
Jill下午不会在这了，她必须得去看医生。（这不是个人意见，而是事实，生病了必须看医生）
In many countries, men have to do military service.
在很多国家，男性必须服兵役。（这也不是个人意见，而是国家法律规定）
Should & Shouldn't我们用should来表示“是好的，对的事，所以应该做”。相应的，我们用shouldn't 表示“不好的，不对的事，所以不应该去做”。
Tom should go to bed earlier, he goes to bed very late and he's always tried.
Tom 应该早点去睡觉，他睡太晚了，总是困。
相反的：
Tom shouldn't go to bed so late.
Tom 不应该那么晚才睡觉。
You should read more books, and shouldn't watch so much TV.
你应该多读些书，不应该看太多电视。
我们也可以用ought to同等替换should。就像上面的例子：
You should read more books
=You ought to read more books.
你应该多读些书。
It's a good film, you should go and see it.
=It's a good film, you ought to go and see it.
这是部好电影，你应该去看一看。
总结出来就是：
可能发生，may & might同等互换
可以做，现在用can，过去用could
必须做，现在用must，过去用had to；强调个人意见用must，客观事实用have to
应该做不做，就用should 和 shouldn't
