A. You can use should after a number of verbs, especially:
suggest propose recommend insist demand
* They insisted that we should have dinner with them.
* I demanded that he should apologise.
* What do you suggest I should do?
In the same way, you can use should after suggestion/proposal/recommendation etc.
* What do you think of Jane’s suggestion that I should buy a car?
and also after ‘it’s important/vital/necessary/essential that…’
* It’s essential that you should be here on time.
B. You can also leave out should in all the sentences in Section A:
* It’s essential that you be here on time. (= that you should be here)
* I demanded that he apologise.
* What do you suggest I do?
This form (you be/he apologise etc.) is sometimes called the subjunctive.
You can also use normal present and past tenses:
* It’s essential that you are here on time.
I demanded that he apologised.
Be careful with suggest. You cannot use to… (‘to do/to buy’ etc.) after suggest:
* What do you suggest we should do?
or What do you suggest we do? (but not ‘What do you suggest us to do?’)
* Jane suggested that I (should) buy a car.
or Jane suggested that I bought a car. (but not ‘Jane suggested me to buy’)
For suggest ~ing, see Unit 52.
C. You can use should after a number of adjectives, especially:
strange odd funny typical natural interesting surprised surprising
* It’s strange that he should be late. He’s usually on time.
* I was surprised that she should say such a thing.
D. If… should…
You can say ‘If something should happen…’. For example:
* If Tom should phone while I’m out, tell him I’ll phone him back later.
‘If Tom should phone’ is similar to ‘If Tom phones’. With should, the speaker feels that the possibility is smaller. Another example:
* I’ve left the washing outside. If it should rain, can you bring it in?
You can also put should at the beginning of these sentences (Should something happen…):
* Should Tom phone, can you tell him I’ll phone him back later?
E. You can use I should…/I shouldn’t… to give somebody advice. For example:
* ‘Shall I leave now?’ ‘No, I should wait a bit longer.’
Here, ‘I should wait’= ‘I would wait if I were you, I advise you to wait’. Two more examples:
* It’s very cold this morning. I should wear a coat when you go out.
* I shouldn’t stay up too late. You’ll be tired tomorrow.