选词填空 根据短文内容，从方框中选择恰当的单词完成句子并填写在答题卡对应的横线上。部分单词在填入前需进行词形转换,每个单词只能用一次,每空只能写一词。( 共5分)

problem   less   important   healthy   recycle

It is very    小题1:to deal with the rubbish in cities. This is because rubbish not only pollutes the environment but also does harm to people’s    小题2:. We are trying to find some ways of dealing with the rubbish. First, the rubbish can be divided into different kinds. Newspaper and glass can be    小题3:. Used tins can be made into beautiful handicrafts（手工艺品）. Polluted water is a big    小题4:. It must be dealt with properly before we let it flow into the river. Some harmful rubbish can be buried（埋）so that it will cause    小题5:pollution.

关于双向扩散试验，下列说法错误的是（）。

A.可用于抗原抗体定性分析

B.可用于抗原抗体定量分析

C.可用于抗原性质分析

D.可用于抗原抗体半定性分析

E.可用于抗体效价的滴定