Ⅲ. Read each paragraph below. Then tell the topic sentences of them.
All living things on the earth need other living things to live. Nothing lives alone. Most animals must live in a group, and even a plant grows close together with others of the same kind. Sometimes one living thing kills another, one eats and the other is eaten. Each kind of life eats another kind of life in order to live, and together they form a food chain(食物链). Some food chains will break up if one of the links disappears.
Topic sentence:
Why are people afraid of killer bees? People are afraid for two reasons. First, killer bees sting(叮)many more times than usual bees. Killer bees can sting sixty times a minute nonstop for two hours. Second, killer bees attack in groups. Four hundred bee stings can kill a person.
Topic sentence:
One of the opposite points that people often bring up is that they love the way their pets behave, not just look. This gets to AI, which has been developing at a fast pace. We have AI that can beat world masters in chess and go. I have no doubt that we can build AI to mimic(模仿)the behaviour of dogs and cats, if not now then probably within a generation.
Topic sentence:

第一段topic sentence: All living things on the earth need other living things to live.
（答案填：All living things on the earth need other living things to live.）
第二段topic sentence: Why are people afraid of killer bees?
（答案填：Why are people afraid of killer bees?）
第三段topic sentence: One of the opposite points that people often bring up is that they love the way their pets behave, not just look.
（答案填：One of the opposite points that people often bring up is that they love the way their pets behave, not just look.）

1. 第一段：段落主要讲述了地球上所有生物需要相互依赖生存，无法独自存在，并提到了食物链的概念及其重要性。因此，主题句应能概括整个段落的核心内容，即所有生物需要相互依赖生存。
2. 第二段：段落主要讨论了人们害怕杀人蜂的两个原因，因此主题句应直接点明段落中心，即人们为什么害怕杀人蜂。
3. 第三段：段落的核心在于讨论人们喜欢宠物行为的特点，并提到可以通过人工智能模仿这些行为，因此主题句应概括段落中关于宠物行为和人工智能的关系。