题目

I think it a great honor ____ to visit your country. A . having invited B . inviting C . to be invited D . to invite 答案：C下列各组物质不能都由单质间直接化合来制取的是（   ）A．PBr3、PCl5B．HI、FeI2C．HBr、FeBr2D．XeF4、CaF2