No strings attached 无附加条件；毫无保留

例句：

We are giving away free t-shirts, no strings attached.

我们免费赠送T恤，无任何附加条件。

Hop in 上车

例句：

Hop in. You can ride with me to the grocery store.

上车，你可以搭我的车去商店。

I'll be down 我很愿意（加入某个活动）

例句：

I'll be down with whatever you guys want to do tonight.

你们晚上想干啥都无所谓，算我一个。

Just my luck 就是这么倒霉

例句：

Just my luck, my boss asked me to work late tonight.

老板要我晚上加班，我运气就是这么衰。

You know better than that 你不该这么做

例句：

Mary said you were rude to her, you know better than that.

玛丽说你对她很粗鲁，你真不该这样对她。

It serves you right 你活该

例句：

It serves him right. He can't expect to win when he cheats during the game.

他这是咎由自取，他不可能比赛作弊还想拿冠军。

My two cents 我的拙见、看法

例句：

Just to add my two cents, but I believe changing the design will be a better idea.

就是想表达一下我的看法，我相信改变设计是个好主意。