The two sides have reached a partial agreement, but several differences still 　　　________ between them. 

A．happen

B．exist

C．survive

D．appear

有关构造函数的叙述不正确的是

A．构造函数名必须和类名一致

B．构造函数在定义对象时自动执行

C．构造函数无任何函数类型

D．在一个类中构造函数有且仅有一个