Difinitions and Rules of Auxiliay verbs:
・Auxiliary verbs have Primary auxiliaries and Modal auxiliaries.
・Auxiliary verbs are verbs that are used to help main verb.
・Auxiliary verbs can not be used without a main verb.
Be, do, have and their various forms are called primary auxiliaries.
Primary auxiliary verbs are used together with a main verb to give grammatical information and therefore add extra meaning to a sentence, which is not given by the main verb.
・They are used to form the passive voice.
・They are used to form the continuous tense.
・They are used to form the perfect tense.
Be, Do and Have are Primary auxiliary verbs, they are irregular verbs and can be used as main verbs.
But Modal auxiliaries can never function as a main verbs.
The primary auxiliary verb be is used with a past participle to form the passive voice;
be(its various forms) + past participle=passive voice
RED=auxiliary BLUE=past participle
・The money was taken.
・The door was opened.
・He was punished for lying.
The primary auxiliary verb be is used with a present participle to form the progressive aspect
be(its various forms) + present participle = progressive aspect
RED=auxiliary BLUE=present participle
・I am writing.(present progressive)
・I have been writing.(present perfect progressive)
・I was writing.(past progressive)
・I had been writing.(past perfect progressive)
It is the most neutral of all the auxiliaries.
It has no individual meaning but serves as an operator for the formation of the interrogative and the negative of the present simple and past simple tenses and also foremphasis or to convey a coherent style.
There is also a lexical verb "do" (= perform) which has the full range of forms including the present participle doing and the past participle done.
To form negative sentences when the verb is imperative, simple present or simple past.
Do (Did,Does) + not + verb = Negative sentence
・I don't (do not) like cheese.
・I didn't (did not) see the movie.
・She doesn't (does not) watch TV.
In questions involving inversion where the verb is in the simple present or past tense.
There is no do-periphrasis in positive wh-questions beginning with the subject ( What happened?) And in yes-no questions where inversion is not necessary. ( He said that?)
do (did,does) + subject + verb=Question
・Do you like coffee?
・Did you see the movie?
・What kind of coffee do you like?
・Why don't you play with me?
The dummy auxiliary do is used for emphasis in positive statements.
In emphatic expressions where the verb is simple present, simple past or imperative.
do (did,does)+ main verb=emphasis
・I do love you!
・Do shut up!
・You did say that!
・You do look nice today!
・In short answers
Do you smoke? Yes, I do.
You ate my cake, didn't you?
He speaks better than you do.
・To avoid repetition of a previous ordinary verb ( pro-form)
He asked me to leave, so I did so.
The formation of the perfective aspect by combining with past participles.
have (has,had) + past perticiple=perfect aspect
・He has eaten the cake.
・He had eaten the cake before he did homework .
・He will have eaten the cake tomorrow.