Too (clever) by half
可太聪明啦（贬义）；聪明过了头
A：He thought he could get Mr. Green’s money in his pocket but he lost all, he was too clever by half.
B：The fact is he never realizes that. He always starts out tricking others and ends up being tricked.
A：That’s the point. He once lost his briefcase by asking a “blind man” to take care of it for him.
A：他以为自己能把格林先生的钱据为己有，但却一分也没得到，他可是聪明过头了。
B：事实是他从没有认识到这一点。他总是开始时骗别人，到最后却被别人骗。
A：对啦，这才是要害。他曾丢过一个公文包，原因是让一个“盲人”帮他看包。