have作為助動詞，與過去分詞構成各種完成時態，或者與been加現在分詞構成各種完成進行時態。如：
Newton has explained the movements of the moon from the attractions of the earth.
Reluctantly, she opened the door, she had not kept it locked; there had been no need.
Men have been digging salt out of it for six hundred years, and yet there seems as much left as ever.
In another month’s time Mr. Henry will have been teaching here for exactly thirty years.
have作為實義動詞，表示“有”，“吃”，“喝”的意思，註意，它作實義動詞時，在美國英語裏面是作為壹般動詞來用的，所以在疑問句、否定句、部分倒裝句中，要用助動詞do、does或did，並且不能用縮略形式，如：
Bad news has wings.
You’re anemic, you must have some iron.
have可以作為使役動詞來用，後跟賓語，賓語之後又常有不帶to的動詞不定式，或者現在分詞、過去分詞作賓語補語，如：
We now have the problem solved.
I had a tooth pulled out this afternoon.
希望我能幫助妳解疑釋惑。