1.C.起初一看，四个选项好像都在文中叙述过，但仔细分析题干中的“most animals”这一关键词语，便可排除其它选项。在第一段最后一句中可找到答案的出处。

5.What is the second paragraph mainly about?

　A. Some animals and plants cannot live without each other.

　B. Some animals and plants cannot develop their friendship easily.

　C. Some plants eat each other.

D. Some animals live better together.

实战演练答案详解 缤纷自然篇

　Passage 1

　[答案与解析]这篇短文讲述了某些生物的迁移这一自然现象，并分析了迁移的原因。科学家们最近又研究了龙虾海底成群结队迁移的现象。它们选择在每年天气不好的季节里进行迁移，其中的原因及迁移的目的，科学家尚未弄清楚。

4.The Chinese for the word “oxygen” is _________.

　A. 氧气 B. 空气 C. 废气 D.二氧化碳

3.We learn from the passage that corals need plants for _______.

　A. friends B. light C. food D. oxygen

2.The underlined word “they” in the first paragraph means _________.

　A. birds and parasites B. birds and sheep

　C. parasites and sheep D. birds, parasites and sheep

1.Some birds like to sit on a sheep because ________.

　A. they can eat its parasites B. they enjoy traveling with the sheep

　C. they can’t live without its parasites D. they want to find the warm place

5.In what way do you think the sun cannot be harmful(有害的)？

　A. The sun can do harm to your eyes and skin.

　B. It can make rivers too dry.

　C. Without it there would be no life on Earth.

　D. Hot sun on dry land can cause fires.

　Passage 12

　Most animals only have animals of a different kind for food. But sometimes two kinds of animals come together in a partnership (伙伴关系) which is good for them. You may have noticed some birds on the backs of sheep. This is not because they want a ride, but because they find easy food in the parasites (寄生虫) on sheep. The sheep let the birds do so because they can stop the parasites from troubling them. So though they can do with it by themselves, they can do better together with each other.

　Sometimes an animal has a plant partner. The relationship develops until the two partners cannot do without each other. This is so in corals of the sea. Inside their bodies they have very small plants, which act as “cleaners”, taking the useless things from the coral and giving oxygen in return. That is what the animal needs to live. If the plants are killed, or are even kept from receiving light so that they cannot live as usual, the corals will die.

4.All the food we eat comes from ______. And it starts with the _____.

　A. plants; earth B. a food chain; sun

　C. food; sun D. plants; star

3.Why can we still see during the day when the sky is cloudy？

　A. Because we can see all day and all night.

　B. Because the sun can't give us light all day long.

　C. Because the sunlight can shine through the clouds.

　D. Because we can't see at night.

2.What are the two main things the sun gives us？

　A. Light and heat. B. Heat and eggs.　C. Corn and light. D. Wheat and bread.