It's a long time since they left.

　　他們已經離開很久了。

　　It's been two weeks now since she called.

　　她到現在已經有兩個星期沒來電話了。

　　I had been out since I was 17.

　　我從17歲起就公開我是同性戀。

　　The children are completely out of control since their father left.

　　這些孩子自他們的父親離開后就無法無天了。

　　It's been an age since we've seen them.

　　我們有很長一段時間沒有見到他們了。