下面的变量中是是数值变量的是()。
A.性别
B.年龄
C.血型
D.职业
E.疗效
参考答案:B
—Were you all frightened at the sound of the fire alarm?
— No. Everyone stayed _______ and obeyed the police.
A.quiet
B.calm
C.silent
D.peaceful
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