Grasslands need time to rest when cattle and other animals feed on them. Moving animals from one area of pasture to another can provide the time needed for new growth. This is called rotational grazing . Rotational grazing is good for the land and the animals, and it can save money. This form of grazing can reduce the need for pesticide treatments by reducing the growth of weeds. And it can limit the need for chemical fertilizers by letting animal wastes do the job of natural fertilizer. Rotational grazing can even help prevent wildfires by keeping grasslands in good condition. Letting animals feed continually and intensively in the same grazing areas can require costly replanting. Animals eat the most desirable growth first. When that keeps happening, the roots do not have enough time to recover. As a result, less desirable plants may replace them. Intensively used grasslands are also harmed as the soil is continually crushed under the weight of heavy animals. While rotational grazing can save money over time, it also requires planning. And that starts with a good map to mark fences, water supplies and grazing areas. Changing methods of grazing also requires time. Farmers may want to put up electric fences to enclose grazing areas, called paddocks. The paddocks will need water. Some farmers design a path for animals from different paddocks to drink from a common watering place. Farmers can start rotational grazing by removing animals from a pasture when the grass is eaten to less that five centimeters. The pasture is then kept empty until the grass grows to more than fifteen centimeters high. Sheep and goats may require special preparations. They may need stronger fences than other animals. And while they eat the grass, they may need guard animals to protect them from animals that would like to eat them. Why do sheep and goats need guard animals? A) They can easily jump over fences. B) They don't like to stay in the paddock C) wild animals are likely to attack them D) Tigers and lions prefer sheep and goats
C

The coyote , that clever animal of wide-open spaces, has come to the nation's capital. In fact, coyotes have spread to every corner of the United States, changing their behaviors to fit new environments and causing researchers to deal with a troublesome new kind of creature: the city coyote. The coyote originally lived in the middle of the continent. One of its most obvious characters is its smartness, which has made the animal a notorious pest. Hunters trapped, shot and poisoned more than a million coyotes in the 1900s. It's still one of America's most hunted animals. Yet the coyote has survived. How has the coyote shown this extraordinary ability? "I guess if you wanted to use one word, it'd be ' _ '," says Eric Gese, an expert at Utah State University. Coyotes can live alone, in pairs, or in large packs like wolves; hunt at night or during the day; occupy a small region or an area up to 40 square miles; and live on all sorts of food, from lizards and shoes, to ants and melons. Unbelievably people helped coyotes increase when they killed most of the wolves in the United States. The spreading of coyotes into city areas, though, is recent. They travel at night, crossing sidewalks and bridges, running along roads and ducking into culverts and underpasses. No one knows why coyotes are moving into cities, but experts explain that cleverer, more human-tolerant coyotes are teaching urban survival skills to new generations. Occasionally, coyotes might attack human beings. There have been about 160 attacks on people in recent years. Therefore, people have been consistently told not to feed coyotes or leave pet food unsecured. That, plus a large trapping program in the neighborhood, has cut down on the coyote population. According to the passage, to cut down on the coyote population, people are advised to _ . A) leave pet food secured B) keep coyotes in small regions C) force coyotes to live alone D) avoid using trapping programs
A

Whether we find a joke funny or not largely depends on where we have been brought up.The sense of humour ismysteriously connected with national characteristics.A Frenchman ,for instance, might find it hard to laugh at Russian joke.In the same way, a Russian might fail to see anything amusing in a joke which would make an Englishman laugh to tears. Most funny stories are based on comic situations.In spite of national differences, certain funny situations have a worldwide request.No matter where you live, you would find it difficult not to laugh at, say ,Charlie Chaplin's early films.However, a new type of humour, which stems largely from America, has recently come into fashion.It is called "sick humour".Comedians base their jokes on tragic situations like violent (cause by force)death or serious accidents.Many people find this sort of joke distasteful.The following example of "sick humour" will enable you to judge for yourself. A man who had broken his right leg was taken to hospital a few weeks before Christmas.From the moment he arrived there, he kept on pestering his doctor tell him when he would be able to go home.He was afraid of having to spend Christmas in hospital .Though the doctor did his best, the patient's recovery was slow.On Christmas day, however, the doctor consoled him by telling him that his chances of being able to leave hospital in time for New Year celebrations were good.The man took heart and, sure enough , on New Year's Eve he was able to hobble along to a party.To compensate for his unpleasant experiences in hospital , the man drank a little more than what was good for him.In the process, he enjoyed himself and kept telling everybody how much he hated hospitals.He was still mumbling something about hospitals at the end of the party when he slipped on a piece of ice and broke his left leg. The man spent Christmas day feeling miserable because _ . A) the doctor had failed to cure him B) he was not able to be with his friends C) being unable to walk, he did not enjoy the celebrations at the hospital D) he thought he might also miss the New Year's Eve celebration
C