1) sky-high 高得上天

　　These prices are sky-high. Let's go somewhere else to buy shoes!

　　OMG! The temperature is sky-high. It's so hot today!

　　2) The sky's the limit 毫无限制； 没有上限

　　You can do anything you put your mind to! The sky's the limit。

　　3) Reach for the sky 达成的天空，立志做某事

　　Reach for the sky! Because if you miss, you'll still be among the stars!