He came in when I finished writing the letter.

我写完这封信的时候，他进来了。

youdao

He had finished writing the letter when I went in.

我进去时他已写完信了。

youdao

She had finished writing the letter when I went in.

我进去时，她已经写完信了。

youdao

She had finished writing the letter when I went in.

我进去时，她已经写完信了。

youdao