Think of "tell" and you think of speaking, but "tell" doesn't always mean "tell."

說到 tell 這個單字你就會想到跟說話有關的意思，但是 tell 不一定都是「說」的意思。

Let me tell you why.

讓我來告訴你為什麼。

OK, that time I meant speaking.

剛剛那句話的 tell 是指「說」沒錯。

Not only does the verb 'tell' mean "say something to someone," it also has a meaning similar to "know", "recognize", "understand", or "perceive."

動詞 tell 不只有「對某人說某事」的意思，它也有類似「知道」、「識別」、「了解」、或「察覺」等字的意思。

We often use it in combination with the verb "can" to make "can tell" for the present and "could tell" for the past.

我們使用 tell 的時候常常會和助動詞 can 一起用，就會產生現在式的用法 can tell 和過去式的用法 could tell。

I can tell he's from France.

我能察覺出他是從法國來的。

He has an accent!

他有法國的口音！

Or we could tell it was going to rain because of the clouds.

或者是，因為雲的關係，我們可以辨認出到底是不是要下雨了。

We often use it to talk about differences.

我們經常用它來討論差異。

Then, we might use the negative or the question.

然後我們也可以把它用在否定句或疑問句。

Can you tell the difference between this cup and that cup?

你可以分辨出這個杯子和那個杯子的不同之處嗎？

I can't tell the difference between this cup and that cup.

我沒辦法分辨出這個杯子和那個杯子的不同之處。

We often use "can tell" with the pronoun "you" to talk about something that many people should find obvious.

我們經常用把 can tell 和代名詞 you 合用，以表示一件大部分人都應該可以明顯發現的事情。

You can tell he's an English teacher.

你可以輕易察覺出他是一名英文老師。

He knows all the answers.

他知道所有的答案。