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课件网) Unit 5 Look into Science Lesson 28 The new words: Chip Taylor, biology, butterfly, migrate, fantastic, completely, grandchild, female, milkweed, chemical, puzzling Important and difficult points: 1) Fantastic facts about the butterfly have been drawing Dr. Taylor’s attention. 2) Here, as many as 230 million butterflies spend the winter. 3) But in Mexico, people cut down the trees that the butterflies need to rest on because they want more land for farming. 4) This is both puzzling and interesting for many scientists. 学习目标 1 2 Do you like nature Why Lead in Would you like to be a biologist when you grow up Why or why not What mysteries of nature do you know about Ask and answer 新课讲授 Listen and imitate Dr. Chip Taylor teaches biology at a university in the United States. He studies one kind of North American butterfly. Just like a migrating bird，this butterfly travels about 4 000 kilometres south in fall. Fantastic facts about the butterfly have been drawing Dr. Taylor′s attention. Butterflies are beautiful. What do you know about them In Mexico，the butterflies always return to the same small piece of forest，which is only 20 kilometres wide. Here, as many as 230 million butterflies spend the winter. They can cover some trees almost completely. The butterflies that return to the south are the great great grandchildren of the butterflies that left for the north. When they begin to travel north in spring，the females lay eggs. They lay eggs on only one plant ： milkweed. But in Mexico，people cut down the trees that the butterflies need to rest on because they want more land for farming. In the United States and Canada，farmers use chemicals that kill milkweed. This worries Dr. Taylor a lot. Now things are improving. Mexico has begun to protect parts of its forests. The United States and Canada have encouraged farmers to use less chemicals. Scientists still don′t understand how the butterflies know when to fly south. If they are even a few days late，they will freeze. And how do all the great great grandchildren find the same forest in Mexico every year This is both puzzling and interesting for many scientists. There are many mysteries yet to be discovered by those interested in science. Would you like to study biology 1. Fantastic facts about the butterfly have been drawing Dr. Taylor’s attention. 这些有关蝴蝶的奇异的事实引起了泰勒先生的注意。 fantastic作形容词，意为“奇异的、极好的、了不起的”，在句中作定语或表语。 e.g. ① I think this is a fantastic invention. 我想这是一个了不起的发明。 ② These flowers are so fantastic. They have many different colours. 这种花太奇异了。它们有很多不同的颜色。 Language points draw one’s attention 引起某人的注意 句中的have been drawing 是现在完成进行时，它由“助动词 have (has) + been + 现在分词”构成，当主语是第三人称单数时用助动词has，其他情况用助动词have。现在完成进行时主要表示从过去开始一直持续到现在的动作，这个动作是否延续下去，要根 ... ...
