I have had enough of your excuses.

have 是助动词，在这里构成现在完成时态。 had 是动词 have 的过去分词形式，have had 构成现在完成时，表示"已经经历过"。 enough 是形容词，意思是"足够的、充分的"，在这里表示"已经达到极限"。 have had enough 是一个固定搭配，表示"已经受够了、无法再忍受"。