Earthquakes strike suddenly at any time of the day or night, but there's no way to tell them. If an earthquake happens, it may cause many deaths and injuries and great damage. Decide how and where your family will get together if separated. Choose an out-of-state friend or   that the family members can call after the quake to report where they are and how they are. Know the safe place in each room: under the strong tables, desks, or against inside walls. Keep enough food, water and other things, including a flashlight, a radio, medicines and clothing.      During the earthquake, you should keep a clear head and never be too nervous to know what to do. Protect your head and neck with your arms. If possible, take a book, a pillow or any other things to protect yourself from falling glass and ruins. If you are indoors, you must immediately lie under any strong furniture. If outdoors, move to an open area away from trees, buildings, walls and power poles. If you are in a narrow valley, move to the centre of it and look out for falling stones. If you are in a car, move to the side of the road and stop the car. Do not stop near buildings, power lines or under bridges. Stay in your car until the shaking stops.      Do not move a badly injured person unless he is in great danger after the earthquake. Do not use the telephone immediately unless there is a serious injury or fire. Turn on your radio for instructions and news report. Be prepared for aftershocks. If you want to leave your home, post a message inside your home telling family members where you can be found. The writer wants to tell us  _  .
why an earthquake is very dangerous. when earthquake usually happen. what to do during and after an earthquake. where to stay during an earthquake.
Question: Earthquakes strike suddenly at any time of the day or night, but there's no way to tell them. If an earthquake happens, it may cause many deaths and injuries and great damage. Decide how and where your family will get together if separated. Choose an out-of-state friend or   that the family members can call after the quake to report where they are and how they are. Know the safe place in each room: under the strong tables, desks, or against inside walls. Keep enough food, water and other things, including a flashlight, a radio, medicines and clothing.      During the earthquake, you should keep a clear head and never be too nervous to know what to do. Protect your head and neck with your arms. If possible, take a book, a pillow or any other things to protect yourself from falling glass and ruins. If you are indoors, you must immediately lie under any strong furniture. If outdoors, move to an open area away from trees, buildings, walls and power poles. If you are in a narrow valley, move to the centre of it and look out for falling stones. If you are in a car, move to the side of the road and stop the car. Do not stop near buildings, power lines or under bridges. Stay in your car until the shaking stops.      Do not move a badly injured person unless he is in great danger after the earthquake. Do not use the telephone immediately unless there is a serious injury or fire. Turn on your radio for instructions and news report. Be prepared for aftershocks. If you want to leave your home, post a message inside your home telling family members where you can be found. The writer wants to tell us  _  .
A. why an earthquake is very dangerous.
B. when earthquake usually happen.
C. what to do during and after an earthquake.
D. where to stay during an earthquake.
Answer: