世界上第一部（）的作者是陆羽。
A.药书
B.农书
C.兵书
D.茶书
参考答案：D
Only when all the fish in the lake died ________ how serious the pollution was.[ ]
A. did the villagers realize
B. the villagers realized
C. had the villagers realized
D. the villagers had realized
构造柱与填充墙的连接处应砌成马牙槎，从每层柱脚开始，先退后进，每一马牙槎沿高度方向的尺寸不宜超过()mm。（）
A.200
B.300
C.400
D.500
