一般来说 have / has 后面不直接加动词原形；当“有”讲时，后面加名词，如 I have a book / She has a car；用作助动词，构成现在完成时时，后面加过去分词，如 I have finished my homework./has/had+Ved(动词的过去分词）表示现在完成时和过去完成时。