() of the land in that district () covered with trees and grass.

A．Two fifth; is

B．Two fifth; are

C．Two fifths; is

D．Two fifths; are

我国产业技术发展要以( )为主要途径。

A．体制和机制创新
B．结构优化和产业升级
C．提高技术创新能力
D．信息化带动工业化