1·Normal methods (those without the exclamation point at the end) modify and return a copy of the string they were invoked upon.
常规方法(结尾没有感叹号)修改并返回调用它们的字符串的副本。
2·The exclamation point methods modify the string which invokes the method.
而带有感叹号的方法直接修改调用它们的字符串。
3·I am sure I will eventually be erected one day become an exclamation point!
我相信，我终究有一天会成为一个竖立的感叹号！
4·Each exclamation point indicates receipt of a reply.
每个感叹号标示一个应答的收据。
5·The height of the exclamation point shall be at least half the height of the triangle, and be centered vertically in the triangle.
感叹号的高度应至少是三角的高度的一半，并垂直居于三角形正中。