parenthesis notation

例句：

1. 1. The sentence structure is often represented by brackets and parentheses.
   句子结构通常用括号和圆括号表示。
2. 2.In mathematics, parentheses are used to indicate operations that need to be performed before the final result.
   在数学中，圆括号用于指示需要在最终结果之前执行的操作。
3. 3.The parentheses in the equation were meant to emphasize the importance of the variable.
   方程中的圆括号是为了强调变量的重要性。