_______ a precious diamond necklace for his wife, Martin could hardly afford a tie for himself.

[      ]

A. Having bought

B. Buying

C. Being bought

D. To buy

下列叙述中不正确的是( )。

A．在C语言中调用函数时，只能把实参的值传送给形参，形参的值不能传送给实参

B．在C的函数中，最好使用全局变量

C．外部变量可以在函数之间传递数据

D．自动变量实质上是一个函数内部的局部变量