用于监测哮喘患者病情的指标是（）
A.用力肺活量
B.PEF日变异率
C.支气管激发实验
D.支气管舒张实验
E.肺泡通气量
参考答案：B
肇庆位于北寒带。[ ]
开放作文。
根据下面英文提示写一篇短文，词数不少于50。
In your English class, you are asked to describe the following picture and explain to your
classmates how you understand it.
提示词 凳子 stool
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