reach for the stars

字面意思是伸手摘星星，实际意思是

to want or try to get something that is difficult or impossible to get

追求难以实现的东西;要做比登天还难的事情;心比天高，延伸出“追寻远大目标”的意思。

比如说

His parents always taught him to dream big and reach for the stars.

他的父母总是教导他要勇敢作梦、立志高远。

"Reaching for the stars" is a good term to use when you want to motivate someone to dosomething difficult.

当你想激励某人去做困难的事情时，reaching for the stars是一个很好的表达。