Using LanguageⅡ教学设计

7选5题设考法：

1.

分布：一般来说，段首挖空有1-2句。段中挖空有2-3句，段末挖空有0-1句。

2.

类型：主题句（小标题，段落主题句），过渡句（段落内部过渡句，段落之间过渡句），细节支撑句（段落中间句子，和主题句比较，支撑句更具体，往往是事实、分析、举例、引用等的一部分。）

3.

技巧：词汇线索（词汇复现，代词），逻辑线索（并列，递进，转折，因果，解释等）

以本课文为材料，根据上面的考法，选择5句挖空，并说出理由。

The possibility of cloning fierce and extinct wild animals has always excited film makers. And they are not the only ones! The popularity of films such as Jurassic Park, in which a scientist clones several kinds of extinct dinosaurs, proves how the idea struck a mixture of fear and excitement into people's hearts. But in fact we are a long way from being able to clone extinct animals. Scientists are still experimenting with cloning mammals. This is because the cloning of mammals is still a new science and its story only began seriously in the 1950s as this list shows: 1950s cloning of frogs 1996 first clone of a mammal: Dolly the sheep 1970s research using the embryos of mice

2000 cow gave birth to a bison 1979 work on embryos of sheep and mice

2001 China's first cloned twin calves 1981 first experimental clones of mice

2002 first cloned cats 1983 first experimental clones of cows

2005 first cloned dog …

From time to time people suggest that extinct animals like dinosaurs, can possibly be brought back to life through cloning. Unfortunately, with what we know now, this is either impossible or unsuitable. There are many reasons. ◎ The initial requirement is that you need perfect DNA (which gives information for how cells are to grow). ◎ All efforts of cloning an animal will be in vain if there is not enough diversity in the group to overcome illnesses. Diversity in a group means having animals with their genes arranged in different ways. The advantage is that if there is a new illness some of these animals may die, but others will survive and pass on the ability to resist that disease to the next generation. The great drawback to cloning a group of animals is that they would all have the same arrangement of genes and so might die of the same illness. Then none of them would be left to continue the species. ◎ It would be unfair to clone any extinct animals if they were to live in a zoo. A suitable habitat would be needed for them to lead a natural life. Based on what we know now, you cannot clone animals that have been extinct longer than10,000 years. Actually, dinosaurs disappeared 65,000,000 years ago. So the chance of dinosaurs ever returning to the earth is merely a dream.