in the first place 首先，从一开始;压根儿;固;当初
In the first place, why should you get married?
首先来考虑这个问题，为什么你要去结婚呢？
Poorer people bought fewer posh brands in the first place.
穷人压根儿不会购买奢侈品。

a defence mechanism 一种防御机制
She's actually rather insecure, and her rudeness is just a defence mechanism.
她其实是缺乏安全感，她的粗鲁不过是出于防卫心理。
They produce light similar to a firefly and use it as a defence mechanism to communicate and to see.
它们像萤火虫一样发光，并用光作为防御机制，进行交流和观察。

play by the rules 按部就班，按规矩办事
If you want to get these guys, you have to keep your mouth shut and play by the rules.
要是你想俘获这些男人，你就要闭上嘴巴、按老规矩行事。
In line with wto standards, us policy should play by the rules of the international economy.
要符合世贸组织标准，美国政策应按照国际经济规则来运转。