古代中国中原人口曾大量南迁,其最主要的原因是 [ ]
A．自然灾害
B．政府徭役
C．战争动乱
D．经营不善
答案：C
Over the past 16 years, the population of the Amish people to 230,000, with roughly 5 children
per family.[ ]
A. had nearly doubled
B. has nearly doubled
C. nearly doubled
D. has nearly been doubling
《烟草建筑设计防火规范》规定，烟叶露天堆场与厂外道路路边间距不应小于（）
A.15m
B.25m
C.20m
D.35m
