A serious earthquake can be a terrible experience, and it is easy to forget safety measures(措施) in disorder(混乱). Fortunately, most earthquake safety measures are common sense, but if you forget everything else, re­member the following instructions: drop, cover, and hold on. Also, most of earthquake deaths hap­pen after the earthquake, so remember that the danger does not end when the shaking does!

     If you stay indoors during an earthquake, move away from unsupported areas and windows. Try to get under a doorway or another area of the building which is held up by strong beams(梁).  Stay under a table or desk only if it is very strong. Do not rush to lifts, because it is far safer to stay where you are. Cover your head with your arms around it and curl (蜷缩) into a ball, and wait for the shaking to stop.

     If you stay outdoors during an earthquake, move to an area which is as open as possible. Don't move to build­ings, electric poles and other objects which may fall during an earthquake and injure you. Protect your head and stay low to the ground till the shaking ends and it is safe to move.

     After an earthquake, many buildings are less strong, although they appear safe. If you stay indoors, move people from the building quickly and help disabled or injured people. Once outdoors, move well away from the building so that if it falls down, you will not be injured. Wait till public safety officials an­nounce that it is safe to stay indoors.

     By planning ahead and keeping calm during an earthquake, you can greatly increase your chances of survival(生存) without injury.

    Air is a colorless, tasteless and invisible（看不见的）gas that is around us. An "empty" drinking glass and an "empty" room, in fact, are not really empty. Each is filled with air. When the glass is filled with water, the water pushes the air out of the glass.

    Air, as a gas, has no definite shape, but because it is matter, it takes up space and it has weight. It is easy to prove that air is something that takes up space. Stuff a piece of dry cloth（布）into the bottom of a glass so that it will not fall out when the glass is turned upside down. Push the upside down glass, holding straight up and down, into a jar of water till the glass is completely covered. When the glass is taken out of the water, the cloth is still dry. The air inside the glass shows that it takes up space and keeps the water from coming in.

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    What picture do you have of the future? Will life in the future be better, worse or the same as now? What do you hope for about the future? Scientists think that life will probably be very different in 2050.

    First of all, it seems that people won't use TV channels by 2050. Instead, people will choose a program from a "menu" and a computer will send the program directly to the television.

    Water will become a very serious problem. We'll need much more water, but there won't be enough. Some scientists think that water would be the cause of war.

    Cars will run on new clean energy and they will go very fast. And there won't be any accidents with the help of computers. On the other hand, space planes will take people around the world in two hours.

   Robots will work in factories instead of people. Many factories have already used robots. Big companies prefer robots—they do not ask for money, and they work for 24 hours a day.

    In a word, by 2050, our life will change a lot and our future will be quite different from now.

    On April 2, we said goodbye to Tiangong I, China's first space lab. According to the China Manned Space Agency (中国载人航天), Tiangong I re-entered the Earth's atmosphere (大气层) and some of its debris (碎片) fell into the South Pacific Ocean.

    There are many spacecraft (宇宙飞船) that are still in orbit(轨道) above the Earth. After finishing their trips, they will all re-enter the Earth's atmosphere like Tiangong I.

    There are two types of re-entries: controlled re-entry and uncontrolled re-entry.

    Some satellites and manned spacecraft come back to the Earth in a controlled re-entry. Experts calculate (计算) the path of the falling spacecraft and its speed. Thy can guide the spacecraft to fall in a chosen area.

    Some spacecraft may have problems while in space after a certain amount of time. These spacecraft come back in an uncontrolled re-entry. It is hard to tell when and where these spacecraft will fall until the last few hours. The US space station Skylab came back partially uncontrolled in 1979. Parts of the station fell in western Australia, but no one was hurt.

    During re-entry, most of the spacecraft will burn up while passing through the Earth's atmosphere. Only a small amount of the debris will reach the ground. The debris typically ends up falling into the ocean, China Daily reported.

    The tiger is the largest wild cat in the world. It is the king of animals. Tigers often eat 5kg of meat for a meal. Tigers can see very well in the dark. They often hunt at night. Sometimes they can eat 27kg of meat at one night. Most members of the cat family dislike water, but tigers enjoy water. They are good at swimming. Many animals live in groups, but tigers live alone（单独地）, except for（除了） mothers and their young babies. A mother tiger usually has two or three babies at one time. She takes care of them by herself.

    There were eight kinds of tigers in the world, but three of them died out（灭绝）. There are only about 3200wild tigers in the world now because people kill tigers and destroy the places where they live.