is even more important is              the earth cooled down, water began to appear on its surface.

A．When; that; when

B．What; whether; as

C．What; that; as

D．lt; whether; as

结构化程序设计主要强调的是( )。

A．程序的规模

B．程序的效率

C．程序设计语言的先进性

D．程序的易读性