The modal verbs are:

can could
may might
shall should
will would

We use modal verbs to show if we believe something is certain, probable or possible (or not). We also use modals to do things like talking about ability, asking permission making requests and offers, and so on.



Dea Mr. Kirk
hello again
and one more question
1-why is this sentence correct? i think what needs to be done is increase(why not is to increase) can we also use is to increase/increasing
2- what should be done is increase(after modal verb should, here we have be and done, so I think they need to be in base form not increase)

Hello again aris,

You can say either 'to increase' or 'increase' in sentence 1. 'what needs to be done' is a relative clause that is the subject of the verb 'is' and then you can use either a base form or an infinitive with 'to' in the complement. By the way, sentences that use a relative clause in this way are called 'cleft sentences'. I don't think we have a page on these on our site, but I'm sure you can find more about them on the internet.

Sentence 2 has essentially the same structure as sentence 1. It uses, of course 'should' instead of 'needs', and so since 'should' is a modal verb, a base form follows it. 'be' is the base form of the passive infinitive 'be done'. 'what should be done', like in sentence 1, is the subject, 'is' is the verb and 'increase' (or you could say 'to increase') is the complement.

I hope this clears it up for you.

All the best,
The LearnEnglish Team

Dear Mr. Kirk
I appreciate your very thorough reply Sir
thanks for the time and willingness you contribute.
God bless you,

dear Mr. Kirk
hello and thank you very much for your help sir.

Dear Sir
Hello, and thank you for answering our questions.
I have come across this: I think what should be done is increase services
I know after a modal we use base forms. but here we have need after the modal.
is this also correct if we use I think what needs to be done is increase services.
one more question can we use both to+verb/verbing in sentences abov
thank you very much again

Hello aris,

I'm afraid I'm not entirely sure I understand your question. I don't see, for example, the word 'need' in the first sentence you ask about – rather there is the verb 'be' (in base form) after the modal verb 'should'. 'need' is not a modal verb, but 'I think what needs to be done is increase services' is correct, so good work there! 

By the way, when you ask about words or sentences in English, I'd recommend using inverted commas to show what words you're asking about. For example, the first sentence you write about is 'I think what should be done is increase services'. By using the inverted commas (' '), it's easier to understand your question.

All the best,
The LearnEnglish Team

Hi teachers,thanks for your useful lessons.

I'm having a homework about exception cases of Can/Could (be able to) are written or used in some special contexts. I tried to search many times at Google but I couldn't find. Could you guide me the way to find them?

Hi Ellie Nguyen,

LIke most modal verbs, 'can' and 'could' have many meanings. They are used, for example, to express ability, permission, probability, possibility and more. In this section (on modal verbs) we organise the information both according to its use (so you can see pages on the above concepts) and its form (so you can see a page on can and could here and here, for example). You can also find more information on modals here.

I hope those pages are helpful.


Best wishes,


The LearnEnglish Team

hi teachers, i have a question for you! i noticed this expression lately:overhead locker space is limited on busy flights your cabin bag may have to go on hands. i was wondering which of this sentence is right 1)the weather is going be bad next week the race may have to bring forward to this one or in this another way ..2)the weather is going be bad next week the race may have to be brought forward to this one.

thank you early.

Hello rosario,

Did you have a question regarding the first sentence? That is a standard phrase in air travel, though I've usually heard it end a bit differently, e.g. '... your cabin bag may have to go under the seat in front of you'. Regarding the other two sentences, only 2 is correct – the past participle 'brought' is needed to form the passive infinitive 'to be brought forward'.

By the way, people usually say 'Thank you in advance' instead of 'thank you early'.

All the best,
The LearnEnglish Team