—That's a big box. Is it heavy? Please let me ____ you.

—No, thanks. It's big, but it's not heavy. [ ]

A. helping

B. to help

C. helps

D. help

下列关于Frame类的说法不正确的是（ ）。

A．在java中允许多重继承

B．在java中一个类只能实现一个接口

C．在java中一个类不能同时继承一个类和实现一个接口

D．java的单一继承使代码更可靠