英语复合词 sky-high 是形容词，表示达到了极高的程度。

例句

Train fares have gone sky-high. I spend half my pay just getting to work!

The prime minister's popularity was sky-high after he cut taxes for everybody.

I'd like to buy a house in the city but prices are sky-high.

请注意

If you say that 'the sky is the limit', it means that anything is possible.

另一个短语是 the sky is the limit, 意思是没有限制，任何可能性都存在。

If you have talent and work hard, the sky is the limit.