Auxiliary Verbs

Auxiliary (=helping) verbs don't mean anything when they are alone, however in sentence they help complete the form and meaning of main verbs. The most common auxiliary verbs are be, have, do.

There are two verbs in each of these sentences:

I	have	lost	my keys.
She	can't	come	to the party.
The hotel	was	built	ten years ago.
Where	do	you	live?

In these examples have/can't/was/do are auxiliary verbs.

OK. So you know what auxiliary verbs are. But when and how can they be used?

Yes, I do, etc.

You can use an auxiliary verb (without the rest of the sentence) when you don't want to repeat something:

• "Have you locked the door?" "Yes, I have." (= I have locked the door)
• George wasn't working but Janet was. (= Janet was working)
• She could lend me the money but she won't. (= she wo't lend me the money)
• "Are you angry with me" "Of course I'm not." (= I'm not angry)

Use do/does/did for the present and past simple:

• "Do you like onions?" "Yes, I do." (= I like onions)
  
• "Does Mark smoke?" "He did but he doesn't any more."

Polite interest

Apart from that, phases such as: have you? / isn't she? / do they? etc. can be used to show polite interest in what somebody has said:

• "I"ve just met Simon." "Oh, have you? How is he?"
• "Liz isn't very well today." "Oh, isn't she? What"s wrong with her?"
• "It rained every day during our holiday." "Did it? What a pity!"

Sometimes we use these "short question" to show surprise:

• "Jim and Nora are getting married." "Are they? Really?"

We use auxiliary verbs with so and neither:

• "I'm feeling tired." "So am I." (= I'm feeling tired too)
• "I never read newspapers" "Neither do I." (= I never read newspapers either)
• Sue hasn't got a car and neither has Martin.

Note the word order after so and neither (verb before subject):

• I passed the exam and so did Tom. (not "so Tom did")

You can use nor instead of neither:

• "I can't remember his name." "Nor can I." or "Neither can I."

You can also use "...not...either":

• "I haven't got any money." "Neither have I." or "Nor have I." or I haven't either."

I think so /I hope so etc.

After some verbs you can use so when you don't want to repeat something:

• "Are those people English?" "I think so." ( I think they are English)
• "Will you be at home tomorrow morning?" "I expect so." (= I expect I'll be at home...)
• Do you think Kate has been invited to the party?" "I suppose so." You can also say I hope so, I guess so and I'm afraid so.

The usual negative forms are:

I think so /I expect so	I don't think so / I don't expect so
I hope so / I'm afraid so /I guess so	I hope not / I'm afraid not / I guess not
I suppose so	I don't suppose so or I suppose not
"Do you think it's going to rain?"	"I think so. / I don't think so."
"Is that woman American?"	"I hope so. / I hope not." (not "I don't hope so")

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