1.That was ingenious.可真是天才．

eg: The design of the new opera house is ingenious.这个新歌剧院的设计真太棒了．　
She's had some ingenious ideas for saving money.她在存钱方面非常有一套．Ｃ

2.This guys are playing for keeps. "play for keeps"＂做事正经些严肃些,当个事办＂
eg: If you're not going to play for keeps you shouldn't bother doing it.你可得正经点否则你最好别介入。

3.It makes perfect sense."make perfect sense"＂很清楚／明白／有道理＂

eg: After i read the textbook the answer made perfect sense to me.读完教科书后我觉得这个答案很清楚明了．