I have had a letter from Tom.第一嘅have 代表?第二had 又是什麼?从句子成分分析~

【I 主语】【 have had 现在完成式谓语动词,have助动词,had实义动词（有,译作收到） 】【a letter宾语】【 from Tom介词短语,定语】例如：
They have had another chance so far.到目前为止,他们还有一次机会.
have had 现在完成时