When an ant dies, other ants take it out of the nest, often within an hour after its death. This behavior interests scientists and they wonder how ants know for sure--and so soon--that another ant is dead. One scientist recently came up with a way to explain this ant behaviour. Dong-Hwan Choe is a biologist, a scientist who studies animals and plants. He found that ants have a chemical on the outside of their bodies that signals to other ants, "I'm dead--take me away" when it is dead. But there's a question to answer: As we know, if an ant is dead, it stops moving. But when an ant is sleeping or knocked unconscious, it is also not moving. However, other ants don't move the living ant out of the nest. How do they know this ant is not dead? Choe found that ants have another chemical on their bodies, which tells nearby ants something like, "Wait--I'm not dead yet" when it is not dead. Choe suspects that when an ant dies, the chemical that says, "Wait I'm not dead yet" quickly goes away. When other ants detect the "dead" chemical without the "not dead yet" chemical, they move away the body. To test his theory , Choe and his team put different chemicals on ants. When the scientists used the "I'm dead" chemical, other ants quickly moved the treated ant away. When the scientists used the "Wait--I'm not dead yet" chemical, other ants left the treated ant alone. Choe believes this behavior shows that the "not dead yet" chemical _ the "dead" chemical when picked up by other ants. And that when an ant dies, the "not dead yet" chemical fades away. Other nearby ants then detect the remaining "dead" chemical and remove the body from the nest. Understanding this behavior can help scientists figure out how to stop ants from invading new places and causing problems. Which of the following descriptions about Dong-Hwan Choe is right? A) Choe did this study in order to stop ants from invading new places. B) Choe is a biologist who is only interested in animals, especially in ants. C) Choe first came up with an idea to explain this ant behavior,and then did some tests to prove his theory. D) Choe did the research on this ant behavior on his own
C
A year ago August, Dave Fuss lost his job driving a truck for a small company in west Michigan. His wife, Gerrie, was still working in the local school cafeteria , but work for Dave was scarce (,), and the price of everything was rising. The Fusses were at risk of joining the millions of Americans who have lost their homes in recent years. Then Dave and Gerrie received a timely gift--$7,000,a legacy from their neighbors Ish and Arlene Hatch, who died in an accident . " It really made a difference when we were going under financially, " says Dave. But the Fusses weren't the only folks in Alto and the neighboring town of Lowell to receive unexpected legacy from the Hatches. Dozens of other families were touched by the Hatches' generosity. In some cases, it was a few thousand dollars ; in others, it was more than $100,000. It surprised nearly everyone that the Hatches had so much money, more than $3 million--they were an elderly couple who lived in an old house on what was left of the family farm . Children of the Great Depression, Ish and Arlene were known for their habit of saving, They thrived on comparison shopping and would routinely go from store to store, checking prices before making a new purchase . Through the years, the Hatches paid for local children to attend summer camp when their parents couldn't afford it. "Ish and Arlene never asked if you needed anything," says their friend Sand Van Weelden, "They could see things they could do to make you happier, and they would do them. Even more extraordinary was that the Hatches had their farmland distributed (;). It was the Hatches' wish that their legacy--a legacy of kindness as much as one of dollars and cents should enrich the whole community and last for generations to come. Neighbors helping neighbors ----that was Ish and Arlene Hatch's story. According to Sand Van Weelden, the Hatches were _ . A) curious B) optimistic C) childlike D) understanding
D
1During the First World War, some Americans indirectly benefited because of the war. With two million white men fighting in Europe and no new immigrants entering the country, many jobs in the United States became available to blacks and women for the first time. 2Both groups proved their ability to do any kind of job. Women became railway conductors, brick layers, and factory workers. Their presence in traditionally male workplace produced many problems. Men were annoyed by women's higher productivity and willingness to work for lower pay. Working mothers were often criticized for leaving their families. But many women welcomed the responsibilities. "It was not until our men were called overseas," said one woman bank executive, "that we make any real onslaught on the realm of finance, and became tellers, managers of departments, and junior and senior officers." 3Women who did not take jobs helped in the war effort in other ways. They made uniforms, rolled bandages, and campaigned for the sale of Liberty Bonds to help finance the war. 4American manufacturers offered jobs to large numbers of black Americans for the first time as a result of the war. Most factories were located in the North. To take advantage of these new job opportunities, many black families moved from their homes in the South to the Northern cities such as Pittsburgh, Cleveland, Buffalo, Chicago, and Detroit. 5White Americans were of two minds about the role of black Americans in the war effort. On the one hand, black workers' ability to learn new jobs quickly and do them well strengthened the home front, and the black men's fighting ability helped the Allies win the war. However, many whites did not want to acknowledge that blacks were capable, effective workers. White soldiers returning from the war had no desire to compete for jobs with blacks on equal terms. At the same time, many blacks were not willing to a lesser role once the war had ended. Which of the following is Untrue according to the above passage? A) Blacks women were not allowed to fight in World War I. B) All American women went to work during World War I. C) Northern cities applied more blacks during World War I. D) Women and blacks earned a lot during World War I.
B