Read the following article and select the best answer. Article: In the 1950s, a family that owned a farm near Beulah, Michigan kept a bull chained to an elm . The bull paced around the tree, dragging the heavy iron chain, which led to a groove in the bark . The groove deepened over the years. Though for whatever reason, it did not kill the tree. After some years, the family took their bull away. They cut the chain, leaving the loop around the tree and one link hanging down. Then one year, agricultural disaster struck Michigan in the form of Dutch Elm Disease. All of the elms lining the road leading to the farm became infected and died. Everyone thought that the old elm would be the next. The farm owners considered doing the safe thing: pulling it out and cutting it up into firewood before it died. But they simply could not bring themselves to do it. It was as if the old tree had become a family friend. So they decided to let nature take its course. Amazingly, the tree did not die. Nobody could understand why it was the only elm still standing in the county! Plant experts from Michigan State University came out to observe the tree. They observed the scar left by the iron chain, now almost completely covered by bark. The experts decided that it was the chain that saved the elm's life. They reasoned that the tree must have absorbed so much iron from the chain that it became immune to the virus. It's said that what doesn't kill you will make you stronger. Or, as Earnest Hemingway put it, "Life breaks us all, but afterwards, many of us are strongest at the broken places." Question: What actually saved the elm? - The bull. - The groove. - The iron chain. - The experts.
The iron chain.

Read the following article and select the best answer. Article: "In the online world you don't need to fill buildings or lecture theatres with people and you don't need to be trapped into a lecture timetable," says Peter Scott, director of the Open University's Knowledge Media Institute. The Open University, the UK's open access university, which allows people to study from home in their own time, has been an international pioneer of degree courses online. The university, with more than 263,000 students in 23 countries, has become a record breaker on the iTunes U service, which provides a digital library of materials for university students and staff.Instead of music or movies, Apple's iTunes U provides a download service for lectures and resources from universities around the world.Top universities from the Massachusetts Institute of Technology and Harvard in the US to Oxford and Cambridge in the UK have been making their materials available, with no charge to the users. There have been 31 million downloads of OU materials, more than any other university, representing roughly 10% of all iTunes U downloads.Nearly 90% of these users are from outside the UK.In this online era, the OU student is also getting younger.A quarter of students are aged under-25 and only 10% are aged 50 or over.That change can only be accelerated as the cost of going to university increases in many countries.The prospect of learning from Harvard from your own bedroom is getting closer. "We have a belief that a degree and an opportunity are rights for all citizens.And we have got to enable the population of students attending higher education to scale up.What I am most excited about is that the privilege of going for higher education is not something only for the wealthy or for the smartest or for the most well-equipped students in the future," an American educator says.Online education will be a way of opening up more choices and getting beyond the big brand names of the most exclusive universities. At the Open University, Peter Scott says they are trying to develop services that give students... Question: According to the passage, we can infer that _ . - all the citizens can get the higher education now - online education will take the place of the traditional education - online education will probably change the way that people go for higher education - studying in Harvard or Cambridge will become easier in the future
online education will probably change the way that people go for higher education

Q: Read the following article and select the best answer. Article: When policy experts debate climate change solutions, they often talk about "a price on carbon." They are arguing about whether companies should pay when they put carbon pollution in the air. Proponents say that it's simple economics -- if it's free to pollute, you'll get a lot of pollution. Opponents claim it will raise the cost of energy that's produced from high carbon sources, like coal. But here's the secret that most people seem to be missing: There already is a price on carbon, and it's paid by the taxpayers. Carbon pollution, like every other form of pollution, has an impact on the environment. Throwing waste into a river will cause the fish to die and the people who drink the water to get sick. And when you produce carbon pollution, you get climate change -- sea level rise, stronger storms, severe droughts, damage to agriculture, and more. All of those impacts cost money. Insurance rates go up when storms get more destructive. Taxes increase when cities have to rebuild bridges and roads. Military budgets go up when droughts and population changes cause conflicts. Not to mention impacts on agriculture and health care costs. In other words, the price on carbon is what we all pay when there is no market force to limit the pollution that causes climate change. So the debate is really about who will pay that price -- the companies who are making a profit from the fossil fuels, or the taxpayers who pick up the cost now? Right now, we have private profit and public cost. It's just like if we allowed every business to throw its garbage in the street because it's too expensive to have it moved away properly. Does it add a little bit to your dinner check to require that restaurants dispose of their trash properly? Sure. But it would be more expensive for you if the city had to clean the streets of their garbage every day. So just like we put a "price on garbage" we need a "price on carbon pollution." Now, a "price on carbon pollution" can mean a lot of things. You could tax companies based on the amount of... Question: The author referred to restaurants in the passage mainly to _ . - prove every business doesn't perform its duty. - warn readers to protect the environment around. - explain the damage of no policy on carbon pollution. - show some restaurants throw away their trash randomly.
A: explain the damage of no policy on carbon pollution.