3C认证模式为（）
A、型式试验
B、初始工厂审查
C、获证后监督
D、型式试验、初始工厂审查、获证后监督
参考答案：D
_____ of the land in the district _____ covered with trees and grass.[ ]
A. Two fifth; is
B. Two fifth; are
C. Two fifths; is
D. Two fifths, are
模地
