81是9的多少倍？

阅读理解。

    Scientists (科学家) are trying to make the deserts (沙漠) into good land again. They want to bring water

to the deserts, so people can live and grow food. They are learning a lot about the deserts. But more and more

of the earth is becoming desert all the time. Scientists may not be able to change the desert in time.

    Why is more and more land becoming desert? Scientists think that people make deserts. People are doing

bad things to the earth.

    Some places on the earth don't get very much rain. But they still don't become deserts. This is because

some green plants are growing there. Small green plants and grass are very important to dry (干的) places.

Plants don't let the hot sun make the earth even drier. Plants don't let the wind blow (吹) the dirt (土) away.

When a little rain falls, the plants hold the water. Without plants, the land can become a desert much more

easily.

1. Deserts ______. [ ]

A. get very little rain

B. never have any plants or animals in them

C. can all be turned into good land soon

D. both A and C

2. Small green plants are very important to dry places because ______.[ ]

A. they don't let the sun make the earth even drier

B. they hold water

C. they don't let the wind blow the earth away

D. all of the above

3. Land is becoming desert little by little (渐渐地) because ______. [ ]

A. Plants can't grow there

B. There is not enough rain

C. People haven't done what scientists wish them to do

D. Scientists know little about the deserts

4. Which is the main idea of the first paragraph (段, 节)? [ ]

A. Scientists know how to change desert into good land.

B. Land is becoming desert faster than scientists can change it back into good land.

C. If scientists can bring water to desert, people can live and grow food there.

D. More and more places are becoming deserts all the time.

5. After reading this, we learn that ______. [ ]

A. plants can keep (阻止) dry land from becoming desert

B. it is good to get rid of (去除) the grass in the deserts

C. all places without much rain will become deserts

D. it is better to grow crops (农作物) on dry land than to grow grass

落实科学发展观，转变经济增长模式，建设资源节约型、环境友好型社会是今后社会发展的总趋势。结合世界能源消费构成比例图，回答各题。

小题1:下列关于世界能源消费构成变化的叙述，正确的是：

①能源的消费地位能够体现一个时代经济发展水平

②20世纪世界能源消费构成的主体是煤炭

③目前煤炭的能源地位下降主要是因为其储量小，开采量减小

④未来世界能源消费构成中占主要地位的是太阳能、核能、生物能等新能源

A．①②③

B．②③④

C．①②④

D．①②③④小题2:针对我国能源利用现状，应采取的最根本措施是：

①调整工业结构，控制高能耗企业的盲目发展 ②使用廉价、清洁燃料

③调整能源消费结构，开发利用新能源     ④关停高能耗企业，达到节约能源的目的

A．①②

B．①③

C．②④

D．①④

封套

被狗、猫等动物咬（抓）伤后，应立即到医疗门诊接种人用狂犬病疫苗。第一次注射狂犬病疫苗的最佳时间是被咬伤后的（）小时内。

A.6

B.12

C.24

D.48

关于麻疹临床表现叙述正确的是

A．潜伏期在5天左右
B．为淡红色充血性斑丘疹，压之不褪色
C．多在发热后3～4天出现皮疹
D．麻疹恢复期为出疹1周后
E．以上均正确