下面的短文后列出了7个句子，请根据短文的内容对每个句子做出判断：如果该句提　供的是正确信息，请选择A；如果该句提供的是错误信息，请选择B；如果该句的信息文中没有提及，请选择C。

　　Earthquake

　　How does an earthquake start？

　　What makes an earthquake happen？ The rock of the earth’s crust （地壳） may have a fault’， a kind of break in the surface. The blocks which make up the earth move， and sometimes this may cause the sides of the fault to move up and down or lengthways （纵向地） against each other. When one piece of rock starts to rub on another with great force， a lot of energy is used. This energy is changed into vibrations （振动） and it is these vibrations that we reef as an earthquake. The vibrations can travel thousands of kilometers and so an earthquake in Turkey may be felt in Greece.

　　What to do during an earthquake？

　　At school

　　As soon as the earthquake starts， students should get under the desks immediately and wait until the teacher tells them it is safe to come out. The teacher should， at the same time， go immediately to the teacher’s desk， get underneath （在……下面） it and stay there till the danger is over. Students must not argue with the teacher or question instructions.

　　As soon as the tremors （震动） stop， all students should walk towards the exit and go straight to the school playground or any open space such as a square or a park. They must wait there until the teacher tells them it is safe to go.

　　At home

　　If you are at home when the earthquake occurs， get immediately under the table in the living room or kitchen. Choose the biggest and strongest table you can find. You must not go anywhere near the window and don’t go out onto the balcony （阳台）。 Once the tremors have stopped， you can come out from under the table but you must leave the building straight away. You should walk down the stairs and should not use the lift - there may be a power cut as a result of the earthquake and you could find yourself trapped inside the lift for hours.

　　In the street

　　If you are in the street when the earthquake takes place， do not stand near buildings， fences or walls —— move away as quickly as possible arid try to find a large open space to wait in. Standing under trees could also be dangerous.

　　16 People knew long ago how an earthquake starts

　　A.Right
　　B.Wrong
　　C.Not mentioned

　　17 Thousands of people were killed during an earthquake in Turkey.

　　A.Right
　　B.Wrong
　　C.Not mentioned

　　18 As soon as an earthquake occurs， students should leave the building

　　A.Right
　　B.Wrong
　　C.Not mentioned

　　19 Students should go to the school playground or an open space once the tremors stop.

　　A.Right
　　B.Wrong
　　C.Not mentioned

　　20 If you are at home when an earthquake occurs， stand near a big table

　　A.Right
　　B.Wrong
　　C.Not mentioned

　　21 The best way to leave the building during an earthquake is to get into a lift

　　A.Right
　　B.Wrong
　　C.Not mentioned

　　22 If you are in the street when an earthquake occurs， stay in a large open space

　　A.Right
　　B.Wrong
　　C.Not mentioned