某厚度为0.75mm的钢板，应采用的焊接方法为( )。
A．手工电弧焊
B．埋弧焊
C．熔化极气体保护焊
D．等离子弧焊
参考答案：D
— Are there any students in the classroom?
— No. __________ there.
[ ]
A. Nobody is
B. Someone is
C. Nobody isn't
D. Someone isn't
接种乙脑疫苗的免疫保护率是（）
A.20%
B.30%
C.40%
D.50%
E.60%以上
