短语讲解：

1. To reinvent the wheel means to waste a lot of time or effort to create something that already exists.

a lot of 诸多; 许多的
例句：I have lost a lot of weight
我体重减了不少。

2. Some word historians say this idiom comes from the American writer Josh Billings.

come from 源自; 来自某处
例句：Ambient noise may come from any direction.
外界噪声可以来自任意方向。

3. His best friend, who makes mistakes often, is in charge of hotel reservations. 
 
in charge of 主管，负责; 照料
例句：He is in charge of the school work.
他负责学校工作。