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右图为气压中心分布示意图①③为大陆上气压中心，②④为海洋上气压中心。完成下列小题。

据图分析这种气压中心分布的形成原因是（）

A.7月副热带高压带被大陆上的低压切断，使副热带高压只保留在海洋上

B.气压带风带随太阳直射点的移动而形成

C.1月，副极地低压被大陆上的冷高压切断，使副极地低压带只保留在海洋上

D.季风气候形成这种气压分布

答案

参考答案：C

解析：

7月副热带高压带被大陆上的低压切断，使副热带高压只保留在海洋上；1月，副极地低压带被大陆上的冷高压切断，使副极地低压带只保留在海洋上。

考点：该题考查高低压中心。

问答题

It was one of those days that the peasant fishermen on this tributary of the Amazon River dream about.
With water levels falling rapidly at the peak of the dry season, a giant school of bass, a tasty fish that fetches a good price at markets, was swimming right into the nets being cast from a dozen small canoes here.
"With a bit of luck, you can make $350 on a day like this," Lauro Souza Almeida, a leader of the local fishermen’s cooperative, exulted as he moved into position. "That is a fortune for people like us," he said, the equivalent of four months at the minimum wage earned by those fortunate enough to find work.
But hovering nearby was a large commercial fishing vessel, a "mother boat" equipped with large ice chests for storage and hauling more than a dozen smaller craft. The crew on board was just waiting for the remainder of the fish to move into the river’ s main channel, where they intended to scoop up as many as they could with their efficient gill nets.
A symbol of abundance to the rest of the world, the Amazon is experiencing a crisis of overfishing. As stocks of the most popular species diminish to worrisome levels, tensions are growing between subsistence fishermen and their commercial rivals, who are eager to enrich their bottom line and satisfy the growing appetite for fish of city-dwellers in Brazil and abroad.
In response, peasants up and down the Amazon, here in Brazil and in neighboring countries like Peru, are forming cooperatives to control fish catches and restock their rivers and lakes. But that effort, increasingly successful, has only encouraged the commercial fishing operations, as well as some of the peasants’ less disciplined neighbors, to step up their depredations.
"The industrial fishing boats, the big 20-to 30-ton vessels, they have a different mentality than us artisanal fishermen, who have learned to take the protection of the environment into account," said the president of the local fishermen’s union. "They want to sweep everything up with their dragnets and then move on, benefiting from our work and sacrifice and leaving us with nothing.\
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计算题
用竖式计算下面各题。
（1）35×46=（2）29×37=
（3）49×82=（4）27×15=
（5）25×75=（6）88×62=
（7）605×25=（8）142×15=
（9）39×47=（10）49×99=
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