A fish out of water:
鱼离开了水 ×
十分不自在 √
例句：
She feels like a fish out of water among the celebrities.
在那些达官贵人中，她感到十分不自在。
Fish tale:
鱼的故事 ×
谎言 √
例句：
Kelly is a master at the fish tale. She should be a politician [ˌpɒləˈtɪʃn].
Kelly真是个谎话精，真应该当个政治家。
Be kept in the dark:
被隐藏在黑暗中 ×
被蒙在鼓里 √
例句：
We were kept completely in the dark about his plan to sell the company.
对他计划将公司出售一事，我们一直蒙在鼓里。
