Modal Auxiliary Verbs
Modal Auxiliary Verbs
Auxiliary means ‘secondary’ or ‘supporting’ and that is exactly what these verbs do. There are only three true auxiliary verbs in English: Have, Do and Be. There are however, other auxiliary verbs that are frequently used in English, modal verbs. Modal verbs tell us how possible, probable or necessary a main verb is.
When using a modal verb in a sentence we do not conjugate (change the tense of) the verb that follows it:
‘He arrives later’ = ‘He will arrive later’
‘The president leaves tonight’ = ‘The president must leave tonight’
‘They visit their mother’ = ‘They should visit their mother’
The following is a list of the modal verbs in their present and past forms. The present forms are used much more than the past forms which are used more in conditional (if/ wish etc.) sentences.
Modal Verbs
100%
S
T
R
E
N
G
T
H
1%
-1%
S
T
R
E
N
G
T
H
-100% |
Present |
Past |
Must |
Had to |
Will / Shall |
Would |
Should / Ought to |
Should / Ought to have done |
May / Might |
May / Might have done |
Could |
Could have done |
Can |
Could |
Would |
Would have done |
Wouldn’t |
Wouldn’t have done |
Can’t |
Couldn’t |
Couldn’t |
Couldn’t have done |
May not / Mightn’t |
May not / Mightn’t have done |
Shouldn’t / Ought not to |
Shouldn’t / Ought not to have done |
Won’t / Shalln’t |
Wouldn’t |
Mustn’t |
Couldn’t have done |
Must (have to)/must not- Must indicates a very strong obligation or necessity. Although sometimes not considered a ‘true’ modal verb, we use have to when the obligation or necessity is external (the obligation comes from someone or something else – not the speaker)
‘We must try to help the environment’ ‘I must eat something’ ‘She has to go now’
Will/shall/won’t/shalln’t- ‘Will’ is used for promises, requests and future forms. ‘Shall’ is less common in modern English but is sometimes used in the same way.
‘I will help you’ ‘Will you help me?’ ‘I will be 30 years old next month’ ‘You shall go to the ball’
Should/ought/shouldn’t/oughtn’t- indicate probability (that something probably will happen) and obligation (something we are obliged to do)
‘It should be sunny tomorrow.’ ‘You shouldn’t forget your mother’s birthday’
May/might/may not/might not- similar to ‘could/ couldn’t’ but not as commonly used, describe a weak possibility, ask for permission (more polite than ‘could’) and give a suggestion.
‘I might finish my work by 12.30’ ‘May I have a glass of water?’ ‘You might study more.’
Could/couldn’t- describe a weak possibility, ask for permission (more polite than ‘can’) and give a suggestion.
‘I could finish my work by 12.30’ ‘Could I have a glass of water?’ ‘You couldn’t study more.’
Can/Can’t/Cannot- indicate ability, permission and possibility
‘I can’t meet you at 1pm’ ‘Can we go?’ ‘It can be difficult to study another language’
Would/Wouldn’t- indicate an unreal form of ‘will’
‘I would give you the answer if I knew it’ ‘She would be happier at home’
Task
Write sentences with each modal verb, in positive and negative forms.
