agoing的用法和樣例：
例句
- All in all, he's more learned than he was ten years ago.
總的說來，他比10年前更有學問了。 - He ran away as a boy thirty years ago, and his family has never heard from him since.
30年前他還是孩子的時候就離開了家，從此，他家裡人一直沒有得到他的消息。 - I've kept up a friendship with a girl I was at school with twenty years ago.
我一直同工同20年前上學時的一位女同學保持著友誼。 - That was 40 years ago, but of course you wouldn't remember it.
那是40年以前的事，你自然想不起來了。
