慢性出血引起缺铁性贫血的疾病有（）
A.钩虫病
B.痔疮
C.溃疡病
D.月经过多
E.胃大部份切除
参考答案：A, B, C, D
As a result of destroying the forest, a large ___ of desert ____ covered the land.[ ]
A. number; has
B. quantity; has
C. number, have
D. quantity; have
计量学是研究测量、保证测量统一和（）的科学。
A.准确
B.标准化
C.安全
D.国际化
