Water is the "life blood" of our earth. It is in every living thing. It is in the air. It runs through mountains and valleys. It forms lakes and oceans. Water is everywhere. Nature has a great water system. Rain water finds its way to streams and the oceans. Here at the mouth of a river there is much important plant and animal life. Pollution destroys this life, so we have to clean out streams and rivers. Man has to work with nature--not against it. There is much plant and animal life at the   _  . A) head of a river B) bottom of a sea C) body of a stream D) mouth of a river
D

Robots make me nervous--especially the ones which seem to think for themselves. I was embarrassed to admit this till I heard that Bill Gates, the founder of Microsoft, felt the same way. Gates said in an interview with the social networking and news website Reddit: "I am in the camp that is concerned about super intelligence. First the machines will do a lot of jobs for us and not be super intelligent.That should be positive if we manage well. A few decades after that though the intelligence is strong enough to be a concern." Well, maybe I don't have to worry about my computer and kitchen equipment yet. After I use them I can always pull the plug. But in the future, machines might find a way to prevent us from switching them off. There's a terrible thought! Maybe the problem with computers too clever for us is not that they are evil like some we've seen in sci-fi movies. What could put us in danger is that they might be too efficient. That's what philosopher Nick Bostrom from Oxford University believes. He says that machines are indifferent   to humans and in pursuit of their own goals,the destruction of people might be just additional damage. Bostrom gives us an example: A machine which might have as its only goal to produce as many paperclips as possible might look at human bodies as extra material for paperclips and go after you. Because it is, well, a machine, it would not take pity on you. It's a good thing that American writer Isaac Asimov thought about how far robots can go and left us his three rules of robotics. They state that a robot may not hurt a human being or allow the human being to come to harm. I'm glad my machines at home are "dumb". All my cleaner wants to take over is the carpet in my living room. Let's hope they don't create an appliance which wants to take over the world!. An intelligent paperclip machine would harm us because   _  . A) it is much cleverer than us B) it would take over the world C) it would see us just as material D) it has the strong feeling of destroying us
C

Elephants are the largest land animals and they need plenty of living space. They have seasonal migration   routes. As human populations rise, elephant land is being cleared for agriculture and other kinds of development.  When animals are effectively trapped on small areas of land, it restricts the gene pool and also results in a shortage of food. Where elephant reserves   border agricultural areas, elephants are often attracted to leave parks to attack crops and barns. Only the strongest walls will stop an adult elephant (males can weigh 6,000kg), so farmers have great difficulty protecting their fields. In prefix = st1 /India, elephants don't only attack for food. Some even have developed a taste for rice beer. InAssam, elephant-human conflict has resulted in the death of more than 150 people and 200 elephants in the space of two years. Poverty leads to the killing of elephants for meat. If people don't have enough food and their governments cannot afford to enforce poaching  bans, it's not difficult to predict the outcome.  Ivory comes form elephant tusks , which can grow to be 3 meters long. Both male and female African elephants have large tusks. Most new ivory comes from Africa and is sold as a high status material in Asian countries such as Thailand, mainlandChinaandJapan. It can fetch $150 an pound and is carved to make decorations, chopsticks and ink stamps. The conservation   priority   here is to change public attitudes. In some countries in southern Africa, where conservation efforts have been successful, there is not enough room for a growing elephant population and animals have to be killed. A CITES meeting in November 2002 ruled that Botswana,NamibiaandSouth Africamay sell stock-piled ivory, starting in2004. Many conservationists are convinced that _ will fuel the demand for ivory and lead to more illegal poaching, they say it is almost impossible to tell legal from poached ivory. The governments argue that the sales will be used to fund conservation work. Which of the following statements is NOT true? A) The increasing human population is the main reason for less elephant land. B) All elephants don't attack for food. C) People in some southern African countries have to kill elephants because elephant-humanconflict is too fierce there. D) Within two years, over 150 people were killed in the elephant-human conflict.
