注射TAT的作用是()
A．中和白喉外毒素
B．中和破伤风外毒素
C．中和所有的外毒素
D．中和病毒
E．刺激人体产生抗毒素
参考答案：B
_____ the people present, I _____ without a word. [ ]
A. If it were not; go
B. Were it not for; would go
C. weren't it for; would go
D. If it hadn't been; would have gone
把精确度为0．02mm／m的水平仪放在1000mm的直尺上，如水平仪的空气泡向左偏移了2格，则说明左边比右边高（）mm。
A.0.01
B.0.021
C.0.03
D.0.04
