Winter begins in the north on December 22nd. People and animals have been doing what they always do to prepare for the colder months. Squirrels  , for example, have been busy gathering nuts from trees. Well, scientists have been busy gathering information about what the squirrels do with the food they collect. They examined differences between red squirrels and gray squirrels in the American state of Indiana. The scientists wanted to know how these differences could affect the growth of black walnut   trees. The black walnut is the nut of choice for both kinds of squirrels. The black walnut tree is also a central part of some hardwood forests. Rob Swihart of Purdue University did the study with Jake Goheen, a former Purdue student now at the University of New Mexico. The two researchers estimate that several times as many walnuts grow when gathered by gray squirrels as compared to red squirrels. Gray squirrels and red squirrels do not store nuts and seeds in the same way. Gray squirrels bury nuts one at a time in a number of places. But they seldom remember where they buried every nut. So some nuts remain in the ground. Conditions are right for them to develop and grow the following spring. Red squirrels, however, store large groups of nuts above ground. Professor Swihart calls " _ ". Gray squirrels are native to Indiana. But Professor Swihart says their numbers began to decrease as more forests were cut for agriculture. Red squirrels began to spread through the state during the past century. The researchers say red squirrels are native to forests that stay green all year, unlike walnut trees. They say the cleaning of forest land for agriculture has helped red squirrels invade Indiana. Jake Goheen calls them a sign of an environmental problem more than a cause. According to the passage, which of the following is true? A) The black walnut is equally attractive to both gray and red squirrels. B) Gray squirrels do more harm to the forest than red squirrels. C) Red squirrels and gray squirrels have helped the spread of walnut trees. D) The cleaning of forest land benefits red squirrels directly.
A

The light is swaying .The building is shaking. A woman with a baby in her arms is trying to open the door, but fails. Finding no way, she rushes into her bedroom and there they  _ the earthquake. In a factory building, as the workshop floor swings  under the terrible shaking, workers run for safety. Some hide under the machines and survive, but others who try to run outside are killed by the falling ceilings. These scenes, played by actors and actresses, are from a film of science education Making a split second decisionshown in 1998 on China Central TV to mark the  22nd anniversary  of the Tangshan Earthquake on July 28. By studying actual cases in the earthquake areas and scientific experiments, experts  found that building remain untouched for the first 12 seconds of an earthquake. In this short time, one has the best chance of surviving an earthquake by staying near the inside walls, in bedrooms and under beds, experts concluded in the film. "Earthquake seems to catch the lives of those who run,"said many survivors in the earthquake areas, describing how their friends were killed on the doorways or along the stair steps as they tried to get out of the building. Their advice was proved in the film,"Take a hiding-place where you are rather than run, unless you are sure you can reach a safe open place in ten seconds." When did the Tangshan Earthquake take place? A) July 28, 1991. B) July 28, 1970. C) July 28, 1976. D) July 28, 1981.
C

On Oct4,2011 , I phone 4s made its international appearance at the press conference claimed by the Iphone cooperation . Ever since then , Iphone4s has become _ and even made a fashion around the globe. Meanwhile , many new expressions come about in relationship with this type of high-tech products. "Jailbreak" is one of them. " Jailbreak" means to unlock the operating system of a mobile phone or other device so that it can run software which it is not normally authorized to use because of restrictions imposed  by the device's manufacturer. If someone jailbreaks a smartphone, tablet computer or other device , they use a special piece of software in order to remove the restrictions imposed by the manufacturer on the kind of applications that can be downloaded and run on the device. The concept of jailbreaking is most often associated with products from Apple Inc, such as the iPhone, iPod and iPad, which routinely restrict the user to applications licensed exclusively  by Apple and purchased via its App Store. As well as wanting to lift the restriction  on what kinds of applications they can purchase, those who jailbreak often do so as a reaction against what they consider as a form of censorship  imposed by Apple Inc in only allowing the use of their 'approved' apps. The concept of jailbreaking dates back to July 2007, when it was applied to the iPhone within a month of the device's first release. This first occurrence related to the adding of custom ringtones , but the idea quickly developed as a means to lift the restriction and equip the phone with games and other applications not licensed by Apple Inc. Which one is the correct statement from this passage? A) The original mobile phones also require jailbreaking B) People jailbreak not only in order to lift the restrictions of applications licensed by the Iphone Cooperation. C) The concept of jailbreak is seldom associated with products from Apple Inc D) The concept of jailbreak dates back to the twentieth century
B

Caffeine not only gives us a daily jump start, but new research suggests it also can strengthen long-term memory. According to the US Food and Drug Administration, nearly 90 percent of people worldwide consume about 200 milligrams of caffeine each day. That' s equivalent to about one strong cup of coffee a day. Writing in " Nature Neuroscience" , Johns Hopkins University researchers say their findings show that caffeine strengthens certain memories for up t0 24 hours after being taken in. " We've always known that  caffeine has  cognitive-enhancing effects   , but its ,particular effects on strengthening memories and making them resistant to forgetting has never been examined in detail in humans, "  said senior author of the paper Michael Yassa. " We re- port for the first time a specific effect of caffeine on reducing forgetting over 24 hours. "      Conducting a double-blind trial, the researchers worked with a test group of people who didn't regularly consume caffeinated products. Five minutes after studying a series of images, the  test subjects were given either a placebo   or a 200-milligram caffeine tablet. To check the caffeine levels of their test subjects, the research team took saliva samples    from them before they took their tablets and again one, three and 24 hours after- wards. Both groups of test participants ( those who took the placebo and those who took the caffeine tablet) were tested the following day to see if they could recognize the images they' d seen the previous day. The test included showing the test subjects another series of images that included some new images , those that were shown the previous day, as well as other images that were similar, but not the same as those they had viewed earlier. The researchers found that more members of the group who were given the caffeine tablets were able to correctly identify some of the new images as " similar" to previously viewed images rather than incorrectly identifying them as the same. "We also know that caffeine is associated with... The purpose of the new research is A) to survey how much caffeine people consume a day B) to write the paper " Nature Neuroscience" C) to prove caffeine has cognitive-enhancing effects D) to examine caffeine ' s memory-strengthening effects in detail

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
D