外幕墙用作外墙立面主要起围护及装饰作用，内幕墙可以用于室内可起到分隔作用。( )
参考答案：对
— _____do they surf on the internet ?
—Twice a week.
A．How soon
B．How much
C．How many
D．How often
下列运算符不能重载为友元函数的是【 】
A．= ( ) [ ] ->
B．+ - ++--
C．> < >= <=
D．+=- =*= ／=
