Modals: will, may, might, can

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Modal Auxiliary Expressions:
can, could, may, might, will

Modal auxiliary expressions are words or phrases that change the meaning of a verb.

Modals are used directly before the verb in a sentence.

Always use the base form of the verb following a modal auxiliary:

Present or Base form	Past form	Present Participle	Past Participle
ask	asked	asking	asked
need	needed	needing	needed
scrape	scraped	scraping	scraped
run	ran	running	ran
give	gave	giving	given
go	went	going	gone

Here are some common modal auxiliaries:

will

may

might

can

could

will
You probably learned that will is part of the future form and this is certainly true. But it is more common to use the going to future than will. English speakers actually use will as a promise more than as a simple future form.

Think about the differences between these sentences:

Future form	I'm going to drive to Paris tomorrow to meet with the program officer.
Promise	I will drive to Paris tomorrow to meet with the program officer.

might, may

Contrast will with might and may. Might and may both mean possibility:

The weatherman said it might rain tomorrow.

I may drive to Paris tomorrow to meet with the program officer.

Both of these sentences reflect possibilities. Might and may mean the same thing in this sense. There is no promise involved, no certainty.

If someone says to you, "I will drive you to work tomorrow," that's good news.
If someone says to you, "I may drive you to work tomorrow," don't forget your bus fare!

may, can

May has another meaning, too. It is used as formal permission.

I-20 students may take a vacation after they have studied in the U.S. for two semesters.

Can is also used for permission, but it is less formal.

Jairo, you can go home as soon as you send that cable.

Jairo: Aye! The boss says I can't leave until I send this cable to Washington!

Look at the difference in tone:

Formal:	Employee manual: Embassy employees may not use embassy cars during those hours when they are not on duty.
Informal:	I'm sorry, Jairo, you can't use the embassy car on weekends.

Could is used as the past tense of can when it means permission.

My boss said I could leave as soon as I send the cable.

But she said I couldn't use the embassy car this weekend.

(Both of these examples are "reported speech.")

can, could

Can also has the meaning of ability. Can means is able to.

Hiroko can speak English very well.

Hiroko is able to speak English very well.

These sentences have the same meaning.

Could is the past tense of can, but it has the additional meaning that a past ability does not exist now.

present ability	Ling can swim very well.	She can swim now.
past ability	Ling could swim very well.	Maybe she broke her arm and she can't swim now!
present ability	Hiroko can speak English very well	English is not a problem for Hiroko.
past ability	Hiroko could speak English very well.	Maybe Hiroko is out of practice!

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