"We have known each other for seven years" 可以用英语表达为 "We've known each other for seven years."。
这句话的来源是指两个人已经认识七年了。
例句：
We've known each other for seven years. 我们已经认识七年了。
It's been seven years since we met. 我们认识的时间已经有七年了。
I can't bepeve we've known each other for seven years. 我不敢相信我们已经认识七年了。