空气压力低于绝对大气压的空间,叫()
参考答案:真空
Be quick! ______________ late for class. [ ]
A. Don't be
B. Not be
C. Be not
D. Be
两只股票的α值分别为( )。
A.1.2%;-1.5%
B.1.8%;-0.5%
C.1.2%;0.5%
D.1.8%;-1.5%