自从他开始新工作以来，他开心多了。

He's been much happier ___since he started his new job.

我从蒂姆七岁起就认识他了。

I've known Tim ___since he was seven.

当我读到这封电子邮件时，我真的很惊讶，因为自从去年我去看你以来，我就没有收到过你的消息。

I was really surprised when I read the e-mail because I haven't heard from you ___since I visited you last year.