What are auxiliary verbs? How to use and example

Auxiliary verbs also known as "helping verbs" are verbs that help the main verbs in sentence by edding additional meaning or forming defferent tenses, moods or voices.

Auxiliary verbs or helping verbs are used before infinitives to add a different meaning. For example you use auxiliary verbs to say:

• That someone is able to do something, 
• That someone is allowed to do something, or
• That someone has to do something. 

The helping verbs are can, could, would, should, ought to, will, shall, may, might and must.

Can and could 

Use can and could to say that someone is able to do something. 

• She can draw really good pictures. 
• Phillip can run fast than Matt.
• Can you ride a bike?
• Can you help me my homework?
• She could already read before she started school. 
• Our teacher said we could go home early. 
• I ran as fast as I could. 
• Sarah could not come to the part because she is ill. 

Note: could is the past tense form of can. Whe you put not after can, write it as one word :cannot. 

They cannot find their way home. 

The contraction of cannot is can't and the contraction of could not is couldn't. 

They can't find their way home. 

I'm full. I can't eat any more. 

Sarah couldn't come to the party because she was ill. 

You may also use can and could to say that someone is allowed something. 

• My mom says you can come to our house for dinner. 
• Dad says I can't walk to school on my own.
• Mom said I could have ice cream after my dinner. 
• You can't go in there without ticket.
• The big sign on the gate said PRIVATE, so we couldn't go in.

Can and could are also used for asking for information or help, for offering something, and suggesting something.

• Can you tell me if this train goes to Topeka?
• Could you show me where the accident happened?
• Could you that window, please? 
• You can borrow my pen if you like. 
• Your sister could come with us, if she wanted to.
• I could lend you my football. 
• We can go to the library instead. 
• John can borrow his brother's skates.

Will and would

Use Will and would when you are asking someone to do something. 

• Will you please stop making that noise?
• Would you pass me that book, please?
• Please, will you close the door?

You can also use will and would to offer something or to suggest something.

• Will I hold this end of the rope?
• Will I carry the bag for you?
• Would you like another drink?
• Which cake would you like?

Notes: the contraction of will not is won't and the contraction of would not is wouldn't:

Won't you stay and eat with us?

Wouldn't it be better to wait?

Shall and Should 

You can use shall and should to ask for advice, offer something and suggest something.

• Should I bring waterproof clothes?
• Should I phone the police?
• Shall we go home now?
• Shall I go by car, or will it be better to walk?
• Shall I help you with that heavy bag?
• You shoud try that new French restaurante. 

Ought to

You use ought to to make strong suggestions and talk about someone's duty.

• You look tired. You ought go to bed early tonight.
• I ought to get more physical exercise. 
• We ought go lock the door when we leave home.
• You ought to turn off the computer when you're not using it.
• You ought to know how tyo spell your own name. 
• The teacher ought to make his classes more interesting. 

Must

Use must to talk about things that you have to do.

• I must mail this letter today.
• You must speak louder. I can't hear you.
• Children must not play with matches.
• Go to bed now. Oh, must I?
• Why must I do my homework tonight?

Notes: must keeps the same form in the past tense.

The contraction of Must not is mustn't.

She mustn't let the dog sleep on her bed.

May and might

Use may to ask if you are allowed to do something and to tell someone that they are allowed to do something. 

• May I go out to play now? Yes, you may.
• May I borrow your pen?
• Please may I see your ticket?
• John may leave now, but Sally may not. 
• May Kenny come with us to the movies?

Use may and might to talk about things that are possible or llikely. 

• Take an umbrealla. It might rain.
• I may not leave have time to go swimming tonight. 
• We might go to the party late.
• If you're not careful, you may hurt yourself.
• Are you going to the concert? I don't know. I might or I might not.