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问题 解答题
计算题
（1）
1
1×2
+
1
2×3
+
1
3×4
+…+
1
2009×2010
；
（2）
1
1+2
+
1
1+2+3
+
1
1+2+3+4
+…+
1
1+2+3+…+2009+2010
．
答案

（1）

1
1×2
+
1
2×3
+
1
3×4
+…+
1
2009×2010

=1-

1
2
+
1
2
-
1
3
+…+
1
2009
-
1
2010

=

2009
2010
；

（2）

1
1+2
+
1
1+2+3
+
1
1+2+3+4
+…+
1
1+2+3+…+2009+2010

=2×（

1
2
-
1
3
+…+
1
2010
-
1
2011
）

=

2009
2011
．

选择题

2005年5月，在纪念世界反法西斯战争胜利60周年时，普京总统说：“苏联解体是20世纪最大的政治悲剧。”苏联解体的根本原因是（ ）

A．制度因素：高度集中的政治经济体制影响了其发展

B．外部因素：西方资本主义国家的“和平演变”

C．领导因素：戈尔巴乔夫和叶利钦加快了苏联解体的过程

D．民族因素：民族问题是毁灭联盟的火药桶
查看答案
单项选择题

B

Uncle Li and Uncle Wang are good friends. They live next to each other and their farms are both at the foot of the mountain. So they can help each other. But neither of them likes to use his head. They’re both poor though they work hard. Most villagers have built new houses, but they still live in the low and broken houses. They never find out why.

Once Uncle Li went to the town to buy some medicine for his wife. In the town he heard the apples in a city were expensive. He told Uncle Wang about it as soon as he went back. They decided to carry some apples to the city. They borrowed some money from their friends and bought nearly 1000 kilograms of apples in the villages and carried them to the city on a tractor. Bad luck! A lot of apples has already been carried there when they arrived. A few days later they had to sell them at a low price. They felt unhappy and returned to their village.

"I can’t understand why we sustained (蒙受) losses in business while others always profit (赢利)" Uncle Li asked one day.

"The tractor was too small " Uncle Wang said without thinking. "We’ll carry more apples on a truck next time !"

"I agree!" said Uncle Li. "How foolish we were!\

Uncle Li and Uncle Wang were unhappy because（）.

A．they had sustained lasses in business

B．they had lost some money in the city

C．something was wrong with the tractor

D．other people profited in the city
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