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高级课程
第07单元第07课时

高级课程» 第7 单元» 第7 课时» 活动中心

 1 Crabs Cause Problems — Basic Story

Some crabs are causing many problems for rivers and streams. People are worried. They are trying to find ways
to get rid of them.
These crabs are said to be a special food in China. Some people think that they were brought from China to
California about ten years ago. Since then there are many more of these crabs.
These crabs are making the sides of rivers and streams weak. This can be very dangerous. If the sides of the
rivers and streams get too weak they can break and cause flooding.
People are trying to find ways to keep the crabs out of certain areas. They are using screens to do this. The
screens are big enough to let fish through but small enough to block the crabs.
Other people are collecting the crabs. They want to learn more about them. They hope to find a way to keep
them from having babies.

 2 cause

to make something happen

 3 collect

to gather and keep things

 4 crabs

water creatures with hard shells and ten legs

 5 dangerous

not safe

 6 flooding

overflowing with water

 7 problems

things that are causing bad things to happen

 8 river

a large body of moving water

 9 screen

fence with holes to let smaller things go through

 10 special

not common or ordinary

 11 weak

not strong

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