Complete the following passage with the words or phrases in the box. Each can be used only once.(将下列单词或词组填入空格，每空格限填一词，每词只能填一次)

 Today I'm going to talk about rainforests. Are you  ____    with them? They're interesting and exciting places! Many kinds of the world's plants and animals live in the rainforests.

 However, rainforests are____ now---they are disappearing very fast because they are cut down or burnt every day. As a result,   ____  animals and plants are dying out.

 Maybe you have never been to a rainforest, so why should you protect them  ____  ?  Rainforests are important to everyone. They are important because the plants in the rainforests make oxygen . We need oxygen to breathe.

（1）取少量Fe₂O₃粉末（红棕色）加入适量盐酸，反应的离子方程式为____ ．反应后得到棕黄色的FeCl₃溶液．用此溶液做以下实验：

（2）取少量溶液置于试管中，滴入NaOH溶液，看到有红褐色沉淀生成，反应的离子方程式为____ ．

（3）在小烧杯中加入25mL蒸馏水，加热至沸腾后，向沸水中加入2mL FeCl₃饱和溶液，继续煮沸至溶液呈____ 色，即可制得Fe（OH）₃胶体．

（4）另取一小烧杯也加入25mL蒸馏水后，向烧杯中也加入2mL FeCl₃饱和溶液，振荡均匀后，将此烧杯（编号甲）与盛有Fe（OH）₃胶体的烧杯（编号乙）一起放置暗处，分别用激光笔照射烧杯中的液体，可以看到____ 烧杯中会产生丁达尔效应．此实验可以区别____ ．

（5）取乙烧杯中少量Fe（OH）₃胶体置于试管中，向试管中滴加一定量的稀盐酸，边滴边振荡，可以看到的现象是____ 、____ ，此变化的离子方程式为____ ．

（6）已知明矾能净水，理由是____ ．

小刚同学在“探究平面镜成像特点”时，选取两段相同的蜡烛A和B，点燃玻璃板前的蜡烛A，并移动玻璃板后的蜡烛B，使它与蜡烛A在玻璃板里的像重合，如图所示，以下说法正确的是（　　）

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