我看完了英语怎么说

“I have read it” 或者 “I have finished reading it” 是最常用的表达方式。来源是英语中的动词"read"，表示阅读的意思。

例句:

I have read the book. (我已经读完了这本书。)
She said she had read the newspaper before breakfast. (她说她早饭前已经读了报纸。)
He has read all the Harry Potter books. (他已经读过所有《哈利·波特》系列的书。)