adj.插入（句）的；括弧（中）的；作为附带说明的；圆括号（弧形）的；弓形的

The parentheses around the numbers indicate they are optional parameters.
括号中的数字表示它们是可选参数。
In the equation (3x + 2)(4x - 1), the parentheses group the terms correctly.
在等式(3x + 2)(4x - 1)中，括号正确地分组了项。
I'll call her later, when I have more time (in parenthesis). (我会稍后给她打电话（顺便说一下），那时我有更多时间。
The author's name is followed by a parenthesis with additional information.
作者的名字后面跟着一个括号，包含额外的信息。
She mentioned, parenthetically, that she had just returned from vacation.
她顺便提到她刚度假回来。
The professor paused to clarify, "(Laughter ensues)." (教授停下来澄清，"笑声随之而来。"
The museum's hours of operation are Monday through Friday, 9am to 5pm (except on holidays). (博物馆的开放时间为周一至周五，上午9点到下午5点（节假日除外）。
The sentence structure was complex, with several clauses nested within parentheses.
句子结构复杂，包含几个嵌套在括号内的从句。
The book discusses various theories (parenthetically, some outdated) in the field of psychology.
这本书讨论了心理学领域的各种理论（顺便提一下，有些已经过时）。
We'll discuss this issue further (if time permits), but for now, let's move on to the next topic.
如果有时间，我们再深入讨论这个问题；但现在，我们先转到下一个话题。