运用“价格变动的影响”的知识，分析价格变动对经济活动有哪些影响？

根据短文内容，选择最佳答案。
    Hello, everyone(每个人)! My name is Bob. I live in Toronto, Canada. It's a very beautiful city. My parents are from France. They speak French. And I can speak English and French.
    I am 13 years old and my birthday is in November. I'm a middle school student. There are thirteen girls and fifteen boys in my class. They are from five countries. They all come to learn English. There are eight Chinese students in my class and six of them are my good friends. I like China very much because it is a great country. I want to learn Chinese. And I want to go to China.

男生逻辑思维敏捷，数理化功课好；而女生在英语、语文等功课上占上风。这启示我们应该（    ）

①欣赏对方的优势，不断完善自己   ②欣赏自己的优势，塑造自我形象

③认识各自的优势，相互取长补短   ④与异性同学相互学习、共同进步

如图所示，甲乙两只完全相同的试管内装有质量相等的不同液体，甲试管竖直放置，乙试管倾斜放置，两试管液面相平．设液体对试管底部的压强为p_甲和p_乙，则下列判断正确的是（　　）

阅读理解

      What would the world be like if cars could drive themselves? Imagine seeing an empty car passing by on its way to pick up its owner, or a car full of passengers who are reading, listening to music or even sleeping. But none of them are worried about the road ahead.

      Well, all of this could be the future of driving. There are several companies, including Google, working on driverless cars. So far, no Google self-driven car has gotten a traffic ticket, but some of them have been in accidents when other cars hit them.

      These cars are now still in the testing stages. But, if the tests are successful, these electric self-driven cars could be put into use very soon.

      The cars already have many features（特点）allowing them to take the place of drivers during certain situations. Some features include cars being able to park themselves, or slow down when they notice objects close by. They can also control the speed if there are dangerous conditions.

      Scientists and engineers believe, with the help of wireless signals, cameras and GPS, we are now at a stage where creating a safe self-driven car might be possible.

      The cause of deadly road accidents is usually careless drivers or dangerous conditions. The self-driven car may be able to prevent these. However, some people do not like the idea. American lawyer Whit Drake, for example, doesn't believe these cars are safe. He thinks that technologies can also be mistakes.

阅读理解

      What would the world be like if cars could drive themselves? Imagine seeing an empty car passing by on its way to pick up its owner, or a car full of passengers who are reading, listening to music or even sleeping. But none of them are worried about the road ahead.

      Well, all of this could be the future of driving. There are several companies, including Google, working on driverless cars. So far, no Google self-driven car has gotten a traffic ticket, but some of them have been in accidents when other cars hit them.

      These cars are now still in the testing stages. But, if the tests are successful, these electric self-driven cars could be put into use very soon.

      The cars already have many features（特点）allowing them to take the place of drivers during certain situations. Some features include cars being able to park themselves, or slow down when they notice objects close by. They can also control the speed if there are dangerous conditions.

      Scientists and engineers believe, with the help of wireless signals, cameras and GPS, we are now at a stage where creating a safe self-driven car might be possible.

      The cause of deadly road accidents is usually careless drivers or dangerous conditions. The self-driven car may be able to prevent these. However, some people do not like the idea. American lawyer Whit Drake, for example, doesn't believe these cars are safe. He thinks that technologies can also be mistakes.