动词have可以作助动词，也可以作实义动词，有五种基本形式，动词原形叫做have，缩略式为've，第三人称单数现在式是has，缩略式为's，过去式是had，缩略式为'd，过去分词是had，现在分词是having，没有haves的形式。它与德文haben与hebben是同源的。
have作为助动词，与过去分词构成各种完成时态，或者与been加现在分词构成各种完成进行时态。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作为实义动词，表示“有”，“吃”，“喝”的意思，注意，它作实义动词时，在美国英语里面是作为一般动词来用的，所以在疑问句、否定句、部分倒装句中，要用助动词do、does或did，并且不能用缩略形式，如：
Bad news has wings.
You’re anemic, you must have some iron.
have可以作为使役动词来用，后跟宾语，宾语之后又常有不带to的动词不定式，或者现在分词、过去分词作宾语补语，如：
We now have the problem solved.
I had a tooth pulled out this afternoon.
希望我能帮助你解疑释惑。