下列关于市净率倍数的说法不正确的是（　　）。

An introductory paragraph must indicate a plan of devel...

单项选择题An introductory paragraph must indicate a plan of development. 
A、正确
B、错误

What's the output of the following code? float area(flo...

单项选择题What's the output of the following code?
float area(float & x)
{
    x = x * x;
    return x;
}
int main ()
{
    float value = 3.0f;
    cout << area(value) << endl;
    cout << value << endl

燃气红外线辐射器的安装高度，不应低于下列哪一项？( )A.2.8mB.3.0mC.3.6mD.4.0m

单项选择题燃气红外线辐射器的安装高度，不应低于下列哪一项？( )