1.一时间 off the top of one's head</STRONG>(英解：without thinking much)-从字面上看，这句话的意思是东西从头上掉下来，指的是临时或没有仔细思索的情况。
A：Do you know that guy?
B:We've met before ,but I cann't remember who he is off the top of my head.
 
2.乐天派 happy-go-lucky</STRONG> (英解：accepting events cheerfully as they happen)
A:It seems like nothing can bring Jerry down.似乎没有事么事情可以使杰瑞忧伤。
B:That's because he's a happy-go-lucky guy. 因 阅读全文>>