代数

He was not good at algebra in middle school.

他中学时不擅长代数。

In algebra, the sign X usually denotes an unknown quantity.

在代数里， 符号X常用来表示未知数。

His classmates were labouring with elementary algebra.

他的同学们正在绞尽脑汁地演算初等代数题。

He would allow John slyly to copy his answers to impossibly difficult algebra questions.

他会让约翰偷偷抄下自己对一些极难的代数题的解答。

Four years after he graduated from school, Tom decided to dust off his algebra book.

汤姆从学校毕业四年后， 决意重温代数。