词汇：

同素异形体　 ____；氨　 ____．铝 ____；合金　 ____；氯气　 ____；reducing agent ____；amphoteric ____；oxidation ____；Silicon ____；acid rain ____

Rainforest also help to ____   the weather. When trees are cut down, it gets hotter. Besides, one quarter of our ____  come from plants. Many of these plants can be found only in rainforests. There is a lot that we have not learnt about rainforests. If we____ them, we will never find out.

In my opinion, our future____ saving the rainforests. We must tell more people how important rainforests are so that they will stop doing harm to them. We must protect the rainforests now. We have to act now to save our only home.

下列有关实验现象的说法，不正确的是（　　）

下列关于群落演替的叙述，正确的是

2016年度，某市新型农村合作医疗人均筹资标准700元，其中个人缴费160元，各级财政补助540元。合作医疗实行零起点报销，不仅患大病的农民可以得到补偿，患小病的农民也能受益。这表明（    ）