But when the weekend comes, it is very cloudy. There is rain in the weather report. In some ways, you may be right. Scientists studied more than 40 years of weather data( 数据 ) from around the world. It shows weekend weather is different from weekday weather in some places. Part of the study involved( 包括 ) 660 weather stations in the US. At more than 230 of these places, the weather on Saturday, Sunday, and Monday was different from the weather on Wednesday, Thursday, and Friday. The difference was small, but the pattern was striking enough to make the scientists take notice. “This kind of weekly rise and fall isn't natural cycles( 自然周期变化 ) . ”the scientists say. Instead, they think that air pollution from human activities makes the weather become different.( ) 1. What's the weather like on weekends?

   All week long, it seems you sit inside at school when it is fine outside. But when the weekend comes, it is very cloudy. There is rain in the weather report.

   In some ways, you may be right. Scientists studied more than 40 years of weather data( 数据 ) from around the world. It shows weekend weather is different from weekday weather in some places.

   Part of the study involved( 包括 ) 660 weather stations in the US. At more than 230 of these places, the weather on Saturday, Sunday, and Monday was different from the weather on Wednesday, Thursday, and Friday. The difference was small, but the pattern was striking enough to make the scientists take notice.

   “This kind of weekly rise and fall isn't natural cycles( 自然周期变化 ) . ”the scientists say. Instead, they think that air pollution from human activities makes the weather become different.

(  ) 1. What's the weather like on weekends?

A. It's rainy.

B. It's sunny.

C. It's cold.

D. It's fine.

(  ) 2. How did the scientists study the weather?

A. They watched the sky.

B. They listened to the weather report.

C. They studied the weather data.

D. They watched the weather report.

(  ) 3. Scientists studied the weather data from     weather stations in the US.

A. 40

B. 230

C. 400

D. 660

(  ) 4. The underlined word “striking” means “    ” in Chinese.

A.细微的

B.严重的

C.明显的

D.大致的

(  ) 5. What makes weekend weather different from weekday weather?

A. The sun.

B. The water.

C. The river.

D. Human activities.