Grammar: Modals Lesson

​A modal is used with a main verb for a purpose.

We use different models for different purposes.

• ​​can

• ​could

• ​will

• ​would

• ​shall

• ​should

• ​may

• ​might

• ​must

• ​ought to

​(a) Can

• ​for ability

• ​for permission

​

(b) Could

• ​as the past tense of can in reported speech

• ​for possibility

​

(c) Will

• ​for future time

• ​for certainty

​(d) Would

• as the past tense of will in reported speech

• ​for intention

• ​for probability

​

(e) Shall

• for future time

• ​for intention

​

(f) Should

• ​for obligation

• ​for what we ought to do when obeying rules

• ​for condition (like if)

​(g) May

• for permission

• for possibility​

(h) Might

• ​as past tense of may in reported speech

• ​for slight possibility

(i) Must

• ​for necessity

• ​for rules

​(j) Ought to

• ​for obligation (what we feel we have to do)

​

​The two words ought and to function as a modal.

Use both of them together.

​

​✘ Mark ought inform his teacher that he was unwell.

​✔ Mark ought to inform his teacher that he was unwell.

​

Note that the reported form of shall is would.

They are modals of intention.

It is wrong to use should since it is a modal of obligation.

​

​"We shall sing together," Mary said.

(changes to)

​

​✘ Mary said that they should sing together.

​✔ Mary said that they would sing together.

​There are two words in most negative modals. However, cannot is only one word.

​Modals (negative form in brackets):

​

• ​can (can't, cannot)

• ​could (couldn't, could not)

• ​will (won't, will not)

• ​would (wouldn't, would not)