Make a mountain out of a molehill:

一座小丘說(shuō)成一座山 ×

小題大做 √

例句：

She shouted at him angrily for being five minutes late, but she really made a mountain out of a molehill.

因?yàn)樗t到了五分鐘，她很生氣地對(duì)他大喊。她真是小題大做。

Break one's back:

背都打碎 ×

非常辛苦地工作 √

例句：

Working as a consultant in this company will break your back. 

在這間咨詢公司上班非常辛苦。

Back the wrong horse:

支持錯(cuò)的馬 ×

押錯(cuò)寶，選錯(cuò)人 √

例句：

He rarely backs the wrong horse when it comes to investing in stocks. 

他在炒股票時(shí)很少看走眼。