Since or For? The Timeline Trick

Lovely! You're chatting with someone new at a party.

真好！你在派對上和一個新認識的人聊天。

They ask, how long have you lived here?

對方問：你在這裡住多久了？

And you say, since three years.

而你回答：「since three years」。

They nod politely... but they look a bit confused.

對方禮貌地點點頭……但看起來有點困惑。

Here's the trick. Picture a timeline.

訣竅是這樣的。想像一條時間軸。

Since points to one moment on that line.

「since」指向時間軸上的某一個時間點。

For measures the whole stretch.

「for」衡量的是整段時間的長度。

Since Monday. Since last summer. Since I was ten.

「Since Monday.」「Since last summer.」「Since I was ten.」

Each one is a single point in time.

每一個都是一個單獨的時間點。

But for three years. For two weeks. For ages.

但是：「for three years」、「for two weeks」、「for ages」。

See? Each one is a length, like a piece of string!

看到了嗎？每一個都是一段長度，就像一截繩子！

Oh, and here's a bonus!

喔，還有一個小彩蛋！

Both usually go with the present perfect.

兩者通常都和現在完成式連用。

I've lived here for three years. I've lived here since last summer.

「I've lived here for three years.」「I've lived here since last summer.」

So next time, ask yourself one thing.

所以下次，只問自己一件事。

Can I point at it on a calendar?

我能在月曆上指出它嗎？

Yes? Since. No? It's a length, so for.

能？用「since」。不能？那是一段長度，就用「for」。

Now, how long have you been learning English?

那麼，你學英文多久了？