允许在饲料添加的药物添加剂是（）。
A．氨苯胂酸预混剂
B．代森铵预混剂
C．替硝唑预混剂
D．亚硝酸盐预混剂
参考答案：A
The number of those missing in the New Zealand's earthquake was reported more than 200, including those discovered bodies that have yet to be ________.[ ]
A. judged
B. recognized
C. identified
D. confirmed
液化石油气在空气中的含量为多大时遇火源会发生强烈的爆炸。（）
A.2-10%
B.2-20%
C.5-20%
D.5-10%
