到你回来时，我已经写完了这本书。

By the time you come back, I will have finished this book.

youdao

昨晚我给父母亲写了一封信。(已经写完了。)

I was writing a letter to my parents last night, when the fire broke out.

youdao

晚饭前我就已经把作文写完了。

I had finished the composition before supper.

youdao

晚饭前我就已经把作文写完了。

I had finished the composition before supper.

youdao