测定环境空气中臭氧的硼酸碘化钾分光光度法,方法灵敏、简单易行,臭氧浓度可在测定的总氧化剂浓度中减去零空气样品浓度得到。
参考答案:对
Many people believe that hunger is only a problem in the developing world. ______, it is a problem all over the world.
A.For one thing
B.In addition
C.As well
D.On the contrary
滤液泵停泵后,要关闭()和冷却水。