预防瓦斯爆炸的措施()。
A.防瓦斯积聚
B.防高温产生
C.防止爆炸灾害扩大
参考答案:A, B, C
Full employment is said to occur when:()
A. the natural rate of unemployment equals zero.
B. the number employed divided by the number in the labor force is less then 5.0 percent.
C. cyclical unemployment equals zero.
下面的组织透明剂一般少用,而且能使阿尼林染料退色的是()。
A.水杨酸甲酯
B.丁香油
C.香柏油
D.氯仿
E.松油醇