如图为三种微生物的结构示意图，请据图回答：

党的十八届三中全会指出：全面深化改革，必须立足于我国长期处于社会主义初级阶段这个最大实际。这表明社会主义初级阶段是（     ）

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Ⅰ.茶叶中铝、铁元素对钙离子的测定有影响，所以要预先除去．

Ⅱ.溶液中铝离子、铁离子完全转化为氢氧化物沉淀的pH在6左右，加热有利于沉淀聚沉．

Ⅲ.茶叶中丰富的有机物来自于植物进行了光合作用．

①称取100g干燥的茶叶，充分灼烧使茶叶灰化，再用研钵磨细后移入烧杯中，然后加入一定量稀盐酸，搅拌、过滤、洗涤．

②向步骤①所得滤液中逐滴加入稀氢氧化钠溶液，调节溶液的pH为6～7左右，再加热煮沸30min，过滤后得到滤液和沉淀．

③向步骤②所得的滤液中加入足量无水碳酸钠，充分搅拌，待充分反应后，过滤、洗涤，得到滤液和沉淀．

请回答下列问题：

     One day, Bob took two of his friends into the mountains. They put up their tents(帐篷)and then rode off to a forest to see how the trees were growing.
      In the afternoon when they were about ten kilometers from their camp(营地), it started to snow. More and more snow fell. Soon Bob could hardly see his hand before his face. He could not find the road! Bob knew there were two roads. One road went to the camp, and the other went to his house, But all was white now. Everything was the same. How could he take his friends back to the camp?
Bob had an idea. The horses! Let the horses take them back! But what would happen if the horses took the road to his house? That would be a trip(行程) of thirty-five kilometers in such cold weather!
      It was getting late. They rode on and on. At last the horses stopped.
Where were they? None of them could tell. John looked around. What was that under the tree? It was one of their tents!