Fly-by-night:
晚上飞过 X
短暂的,不可信任的 √
例句:
Can we believe in the credibility [ˌkrɛdəˈbɪlɪti] of fly-by-night companies?
皮包公司的信誉值得我们相信吗?
Bury the hatchet:
和解,停战;休战 √
例句:
If I were you, I'd bury the hatchet.
如果我是你,我就讲和。
A dog's age:
一只狗的年龄 X
好久,很长的时间 √
例句:
I haven't seen Charlie for a dog's age.
我好久没有见到查理了。
(素材来自学英语口语,如有侵权请联系删除)