Mountains of smoke and fire

Deep under the Earth's surface, it's so hot that even rock melts. Sometimes this molten rock, called “magma”, is pushed up to the surface.   【小题1】 And the opening or vent that lets the lava out is a volcano.

A volcano may explode violently, throwing out rocks for miles around.   【小题2】 Some volcanoes release clouds of poisonous gas or huge clouds of ash. Volcanoes can even do all these things underwater.

Most volcanoes have been around for a very long time. Many haven't erupted for years and have cooled off. Volcanoes that are not going to erupt again are called “dead volcanoes”. Some volcanoes still give off smoke. These “sleeping volcanoes” may “wake up” one day and erupt again.   【小题3】 But one day in AD 79 it suddenly woke up. Its eruption threw out hot ash and rocky fragments (碎片) that buried the city of Pompeii. A hot mud­flow buried nearby Herculaneum. Because the remains are so well preserved, the area has been named a World Heritage site.

But not all volcanoes are destructive. When a volcano throws out vast amounts of lava and debris(岩屑), it piles up into a mountain. 【小题4】

Other volcanoes help provide heat and energy. Many Icelandic homes get their hot water from springs heated by volcanic steam. 【小题5】 Plants grow very well in the rich soil left by volcanoes. And valuable gems, such as diamonds, can sometimes be found in the rocks that are thrown out by volcanoes.

An earthquake is one of the most common natural disasters. It may cause great damage. So it is smart to learn some simple safety tips to protect yourself or your family members.

Fragile items (物品) like those made of glass are easily broken and should usually be placed on a lower surface, near the ground. Never place them near your bed, sofas and other furniture where you would be sitting or lying down. So when there is a strong movement, these pieces will fall on the floor directly, not on you.

There is a strong chance of short circuits and fire during an earthquake. Make sure you turn off power and gas immediately when an earthquake happens.

During an earthquake, lie under an object that is not easily damaged. Do not go near objects that could directly fall on you. Never use the elevator to go down. Stay inside until the shaking stops and it is safe to go outside. Research has shown that most injuries happen when people inside buildings try to go out. Use the staircases (楼梯) at all times.

If you are outdoors, do not take shelter under a tree, streetlights, electric poles or tall buildings. If you are driving, stop your car and stay in a safe place. Do not park your car under a tree or any tall object.

If trapped in ruins, cover your mouth with a handkerchief or clothing. Tap on a pipe or the wall so rescuers can find you. Use a whistle (哨子) if one is available. Never shout for help. Shouting can cause you to breathe in dangerous amounts of dust. Do not light a match because you may burn yourself.

Floods, storms and other natural events kill thousands of people every year.【小题1】In fact, experts say heat may be nature’s deadliest killer. Several hot days that follow each other are considered a heat wave. Heat waves often become dangerous when the nighttime temperature does not drop much from the highest daytime temperature. This puts great pressure on the human body.

【小题2】Amtrak, the passenger railroad service, announced that it was reducing the speed at which its trains travel in the northeast. The reason: extreme heat. Amtrak said it made the decision after the temperature inside some train tracks rose above 48. 9 degrees Celsius. On the other side of the word, the temperature in several Chinese provinces hit over 39 degrees Celsius.

Hot weather is dangerous for people who weigh too much, and for people who drink alcohol.【小题3】 The most common health problem linked to hot weather is heat stress. Usually, it is also the least severe. Untreated heat stress can lead to heat exhaustion, which may also produce a fast heartbeat, breathing problems and pain in the head, chest or stomach.【小题4】

Doctors say people can do many things to protect themselves from the dangers of extreme heat.【小题5】 Drink lots of cool water. Wear light-colored clothing and hats made of natural materials. Make sure the clothing is loose, permitting freedom of movement. Also, learn the danger signs of the medical problems linked to heat.