Pulp (纸浆) magazines were cheap magazines filled with science fictions and adventure (冒险) stories. They were printed from 1896 to the 1950s. People called them "pulp magazines", because the paper used to print them came from wood pulp. This was the cheapest kind of paper. Pulp magazines were popular because they didn't cost much money.

Pulp magazines usually had a very pretty cover picture. It was bright and colorful. It usually showed a woman in trouble and a hero coming to save her. In the magazine, there were many stories written by different writers. Some pulp magazines featured (以……为特色) detective (侦探) stories. There were terror (恐怖) pulp magazines and romance (浪漫) pulp magazines too.

One of the most famous pulp magazines was called Amazing Stories. This was a science fiction pulp magazine. It started in 1926. There were stories of young handsome heroes saving the earth from danger. There were stories that imagined life in the future. Before they were famous, many science fiction writers had begun writing for Amazing Stories. Isaac Asimov, for example, wrote a story called Marooned off Vesta that Amazing Stories printed in 1939.

Many pulp magazines stopped printing in the 1950s. One of the reasons was the growth of the television. Watching TV became a hobby for many people. Paperbacks also became more popular at the same time. They were more expensive than pulp magazines but people had more money than before. They spent it on paperbacks.

Our world is in danger. We must do something to protect the environment. But (A)________ are the main problems we face?

The greenhouse effect

The atmosphere around the Earth is necessary for all living things. It is like the glass of a greenhouse, letting sunlight in and keeping heat from getting out. Without it, the Earth would be the same(B)________ the Moon—cold and lifeless.

When we burn fuels such as petrol and coal, we produce a gas called carbon dioxide(二氧化碳). Too much of this gas pollutes the atmosphere, and causes it to keep in too much heat. As a result of the greenhouse effect, the Earth’s temperature is increasing. This causes sea level to rise, and in the future may cause cities to disappear.

Cutting down forests

Every year, we destroy nature by cutting down huge areas of forests. (C)This makes the greenhouse effect worse (D)take, because, carbon dioxide, trees, in and produce oxygen. Cutting down trees also destroys the homes of the animals that live in our forests, and causes the surface of the soil to be easily destroyed by rain. This can (E) ________ and even more damage to the environment.

Robots are very important in our daily life now. People like robots because they can do things for us. They can do housework. They can deal with data (处理数据) fast. Some people think robots can do everything nicely. But some things that are easy for us are difficult for robots. For example, robots have difficulty picking up things. This may make you feel surprised because even babies can pick up things easily. That’s because our brains tell us how to use our hands to hold things. But robots can’t understand these kinds of things. So they often break or drop things.

Many scientists are trying to deal with this problem. Among them is Ken Goldberg from the University of California, Berkeley, the US. He has studied the problem for years. Finally, he came up with an answer to the question. He built a database for robots. All kinds of information about a thing, such as its size and shape, are in the database. Before a robot picks up a thing, it can find the information about the thing. In this way, the robot can pick up the thing easily.