200平方米比______平方米少20%；比240克多20%的是______克．

数列{a_n}的前n项和为S_n，存在常数A，B，C，使得a_n+S_n=An²+Bn+C对任意正整数n都成立．若数列{a_n}为等差数列，求证：3A-B+C=0．

融合牙是（）。

A.仅见于乳牙

B.仅见于恒牙

C.两牙牙釉质相连

D.两牙牙本质相连

E.两牙牙骨质相连

和平与发展是当今世界的两大主流。( )

阅读理解。

     I chose to study in Madrid because I had a desire to learn Spanish. My first impressions of Madrid

were incredible. It was before the New Year that I arrived in Madrid for the first time. While traveling

to my Spanish friend's house in a taxi, I appreciated the buildings along the road which were different

from those of my own country.

     There are an incredible number of restaurants and bars from all over the world. If you are really into

sightseeing, I hope you have rechargeable batteries for your digital camera, because one week really isn't

enough time to see everything here including a number of art, science, and historical museums as well as

parks, buildings, and amazing landscapes.

      What I liked best about life in Madrid was the fact that if you were frustrated with schoolwork and

wanted to have some fun, you can easily go out. The nightlife never seems to stop and the people are all

very friendly. You can meet people and practice Spanish while having fun at the same time.

      What I liked least was the fact that many people smoked in the streets. Also, coming from the US,

I was used to having a big breakfast every morning, but while living with an actual Spanish family, I wasn't

really satisfied with the food in the morning.

      I think I have definitely become more independent since I came back from Spain. Living in a big city

like Madrid I found that it is necessary to plan ahead and to make a schedule (时间表) for future. There is

so much to see, not just in the Spanish World, but in the European World as well.

1. What's the purpose of the text? [ ]

A. To attract people to tour around Madrid.

B. To show how to enjoy Spanish culture.

C. To give advice on how to study Spanish.

D. To describe the author's life in Madrid.

2. The author went to Madrid to _____. [ ]

A. visit his friend

B. go on a sightseeing tour

C. study Spanish

D. complete his trip around Europe

3. Why did the author suggest taking rechargeable batteries? [ ]

A. It's difficult to deal with the used batteries.

B. It's not convenient to recharge batteries.

C. There are few stores that sell ordinary batteries.

D. You will find lots of places worth taking pictures of.

4. Which of the following in Madrid didn't please the author? [ ]

A. Parks and buildings.

B. Restaurants and bars.

C. Nightlife.

D. Breakfast.

观光农业的空间功能分区主要由哪些构成？