(2014·东北三校模拟)We had just covered half the journey________the engine failed and we could do nothing but wait for help.

A．before

B．since

C．when　

D．until

C++语言中关于构造函数的说法正确的是( )。

A．构造函数的函数名不必和类名相同

B．构造函数只能每一个

C．每个类必定有构造函数

D．构造函数必有返回值