1. Expression：look a gift horse in the mouth

Explanation：To be ungrateful to someone who gives you something. （对给你礼物的人不感恩反而对礼物吹毛求疵，对礼物挑三拣四，评论礼物的好坏）

Example：I know Aunt Jean isn't your favorite person, but she gave you that beautiful sweater as a present, so don't look a gift horse in the mouth!

我知道珍阿姨不是你最喜欢的人，但她送你那件漂亮的毛衣作为礼物，所以不要对礼物吹毛求疵！

Even though the watch Mary gave you is not an expensive one, you should be quite contented with it and not look a gift horse in the mouth.

即使玛丽送给你的表是便宜货，你也该满足，不应该对礼物说短道长。

It was one of mother's maxims never to look a gift horse in the mouth.

母亲的箴言之一是“受赠之马，不可相嘴。”

A: But I don't want this ancient car!

我不想要这过时的车。

B: I can't believe you're looking a gift horse in the mouth, especially since you can't afford to buy a car on your own!

我真不敢相信你竟然会对礼物挑三拣四，尤其是之前，你自己连一辆车都买不起。

2. Expression：put the cart before the horse

Explanation：To do things out of the proper order. （做事情没有条理，本末倒置）

Example：Wait until we buy a cart before you build the garage; don't put the cart before the horse.

等我们把汽车买到你再建车库好了，不要本末倒置。

No, it's not bankruptcy which has caused him to drink. You've put the cart before the horse.

不，那不是破产使他酗酒的，你可把因果颠倒了。

Starting the fundraiser before we know how much we need is putting the cart before the horse.

在我们知道我们需要多少钱之前就开始募捐是本末倒置。

Aren't you putting the cart before the horse by deciding what to wear for the wedding before you've even been invited to it?

你还没有被邀请去参加婚礼就在决定着穿什么衣服去参加婚礼，这不是本末倒置吗？