情態助動詞 can 的用法

表示有能力(能夠、會)做某事。

My brother can speak five languages.

我哥哥會說五種語言。

I need advice and guidance. Can you help?

我需要建議和指導。 你能幫我嗎？

Linda: Can you drive a car?
Peter: I could drive ten years ago but not now.

琳達：你會開車嗎？
彼得：我十年前會開車，但是現在不能。

could 是 can 的過去式，can 與 could 都可以用來表示有能力(能夠、會)做某事。

can 的否定形式是 cannot 或 can't

Tom can't drive.

Tom 不會開車。

I can't help smiling when I see her.

當我看到她時，我不禁笑起來。

"can't help" - 禁不住， 無法抑制

表示『允許』

Can I ride your bike?

我可以騎你的腳踏車嗎？

上句也可以改為 May I ride your bike? 用 may 比用 can 較拘謹。兩者都有 be allowed to 的意思。

People can't drive before they are sixteen.

人們16前之前不能開車。

can 的否定形式是 can't 或 cannot。can't 不被允許。

Can the government restrict individual liberties to stop the spread of COVID-19?

政府能否限制個人自由以阻止COVID-19的傳播？

答案是肯定的。can (= to be allowed to) 可以，能。

表示『可能』

I wonder if my long-lost puppy can still be alive.

我不知道我那遺失許久的小狗是否還可能存活著。

注意： long-lost 久已不見的； long 與 lost 中間要有 “-”。

can 和 be able to

情態助動詞 can 作為『能夠』解釋時，可以被 be able to 取代。唯一不同的是 be able to 必須考慮前面主詞的『身』與『數』。

I can walk with my two hands.
I am able to walk with my two hands.

She can cope with the work.
She is able to cope with the work.

The researchers were able to determine its age by studying the surrounding rocks and soil.

研究人員能夠通過研究周圍的岩石和土壤來確定它的年齡。

主詞是複數且過去式故用 were able to。

情態助動詞 can't 的猜測用法。

can't have + 過去分詞

我們使用情態助動詞 can't have 來猜測或推斷我們認為「絕對沒有發生」的事情。

She can't have been at the meeting, she is on a business trip this week.

她不可能參加會議，她這個禮拜出差。