广西灾害性天气较为频繁的原因是（ ）
A．距海洋近
B．夏季风进退失常
C．位于祖国南部
D．地势西北高，东南低
答案：B
喝浓茶可促进铁剂的吸收。
In China, students ____ greet the teacher when classes begin.[ ]
A. are supposed to
B. are suppose to
C. suppose to
D. is supposed to
