括号（parentheses）
1、用于分隔句子中不重要的内容。
We visited several European countries (England, France,Spain) on our trip last year.
2、用于在句子中分隔数字。
Grades will be based on (1) participation, (2) in-class writing, and (3) exams.
3、当括号用于在句子中插入句子时，无需使用句号，但插入的句子有问号或感叹号时，应当保留问号或感叹号。
The snow (do you remember what snow feels like?) was falling heavily.
4、当括号用于插入一个独立句子时，标点符号应当在括号内。
I'm not looking forward to presenting to the class on Monday. (My childhood stage fright has never really left me.) I hope I can get it over with quickly.