成年人引起缺铁性贫血的最常见病因是（）
A.铁丢失过多
B.慢性失血
C.铁需求量增加
D.铁吸收不良
E.铁摄入不足
参考答案：B
—Where is Tom?
—He didn't come to school today. I think he be ill. [ ]
A. has to
B. should
C. may
D. need
中距离跳投
