1)Don't act like a child. 别像个孩子似的。

2)Stop acting like a fool. 别傻了。

3)Don't play the fool. 别丢人了。

4)Act your age.成熟一点儿.

5)Don't make an ass out of yourself. 别丢人现眼了。

6)Don't make such stupid mistakes again! 别再犯这种愚蠢的错误了。