Act your age. 你也不看看你多大了。
You should act your age. 你也不看看你多大了。
Behave in accordance with what is expected of your age! 你的行为举止应该跟你的年龄相符。
You should behave more maturely. 你该表现得更成熟些。
You shouldn't act like a child. 别像个孩子似的。
You should get your head out of the clouds. 你的想法太离谱了。
Don't make such stupid mistakes again! 别再犯这种愚蠢的错误了。