Ability
Be able to
Can
Could
Negatives in the past
( we can also use able to in negatives in the past)
We can use be able to particulary in more formal contexts and to talk ability on a
specifi occasion in the past
Less formal, usually prefer with verbs of sense
and verb of thinking
Example: They couldn’t prevent the fire damaging the school’s sports center
Example : The hotels on the island are able to accommodate hundreds of visitors
Example : I can fly like butterflies
Possibility
May
Miight
Used in questions, but is rather formal . Also used to say that things are not possible or that it is possible things are not te case
To talk about more general Possibly of something happening
Example: The temperature in the mountains may fall below freezing even at this time of year
Example: I think we should call off the strike, but other people might not agree with me ( it’s possible that people don’t agree with me )
Conclusions, willingness, habitual events
Will
Would
Used to
We can use will to draw conclusion or state assumptions about things we think are true
We use would to talk about willingness in the future, in conditionals , and when we say that we are willing but unable to do something
Example: No doubt yo will have heard the news by now
Example: Many people would be happy to pay higher taxes for better public services.
We can use either would or used to to talk about things that happened repeatedly in the past
Example: The crossing *used to* take over an hour at least
Necessity, deduction
Must
Have (got) to
We can use either must or have to to say that it is necessary to do something, although have to is less formal and is also preferred in questions
Example: The cabin staff must accept the new working conditions if the airline is to complete
When we say that something was necessary in the past we use had to not must
Example: Up to 200 teachers and pupils had to evacuated from a school in South Wales today
Not necessary
didn’t have to
needn’t have
Didn’t need to
To say it was necessary to do in the past
To say it was necessary to do in the past
When we think something that was done in the past was not necessary we use need not have
Example: He didn’t have to wait long for a response
Example: He didn’t need to wait long for a response
Example: The event organizers expected the bad weather to affect ticket sales. However, they need to have worried, as every ticket was sold
Obligation
Should
Ought to
We can use either should or ought to to talk about obligation
We can use either should or ought to to say that something is likely because we have planned it or expect it to happen
Example: I think we should keep Borland for the islanders !
Example: They say the road will be ready in five years, but they ought to be able to build is faster
Dare and Need
Had better
As modals dare and need are mostly used in negative context. We can use either date to or dare without to when it is not followed by not
But no one would dare to climb up the outside of the building
We needn’t interview everyone in the block
We can use had better instead of should/ ought to, especially in spoken English to say that we think it is good idea to do smth
We’d better find out all we can about that guard as soon as possible
Be supposed to
Be allowed to
We can use could or was/ were allowed to to say that in the past someone had general permission to do something
Only the security guard could/ was allowed to stay in the museum after it closed
We can use be supposed to to express a less strong obligation that with should or ought to
The entry code is supposed to be known only by the security guard