user: *Question*
Howling is a behavior commonly observed among a wolf nark. An animals, wolves work together to hunt and rely on howling was an important means of communication each other. There are different explants of a wolf's howl and it appears that there may be more to discover.      One theory is that wolves howl to bend better together. It's almost as if howling together helps the pack stay together. Perhaps something similar to people feeling a sense of involvement with each other when singing a song together . But this theory may be wrong, explains Fred H. Harington, a professor who studies wolf behavior.     Indeed, there have been tines when wolves have been seen one moment howling in a exhorts, and the next, quarreling anions each other. It appears that usually the lowest-tanking menthes of the pack may actually be "punished" for Joining in the churs at times. So is howling a way to strcagthen a social boad or just a way to reconfirm status among its members? ----Why do welves howl for sure? What is cleat, however, is that howling is often used among packmates to locate each other. Hunting grounds are distant and it happens that woloves may separate from one another at times. When this happens, howling appcars to be an ercellent means of gathering. Howling, interestingly, is a contagious behaviour. When one wolf starts to howl, very likely others will follow. This is often seen to occat in the morning, as if wolves were doing some sotr of "roll rall"where wolves all howl togeter to howl, very likely others will follow. This is often seen to occar in the morning, as if wolves were doing w some sotr of "roll call"where wolves all howl together to repotr their pteence. .What the por similarity between wolves' how humaes ting in chorus? A) The act of calling each other. B) the sense of accomplishment. C) The act of hunting for something. D) The sense of belonging to a group.
**Answer**
D

*Question*
Even when you're extremely busy, you aren't using your time with 100% efficiency. There are gaps in everyone's schedule where they aren't doing anything important. Even if your schedule has no gaps, there is probably lots of time when you aren't working as fast or as effectively as you possibly could. Why aren't you completely efficient? It's because time isn't the limiting factor. If it were the limiting factor, people could work non-stop without breaks or any unproductive distractions  . Instead, people, even those who are highly productive, need to take breaks, occasionally procrastinate   and slow down on tasks throughout the day. The real and most important limiting factor for productivity is your energy levels to pay attention. Energy levels limit your productivity because when you're tired, you can have enough time and still not get everything done. Your attention ability is also limited, because even if there are a million things that need to be done, you can only focus on one or two at a time. You might not be able to insert another 4-5 hours into your schedule without making some sacrifices. But even extremely busy people can add an hour or two into their schedule without cancelling anything. The reason why it's hard to "find time" isn't a lack of time. It's because you don't have enough energy left to focus on something else that needs to fit into your day. I first suspected time wasn't the real problem during an extremely busy period in my life over a year ago. I was extremely busy, but at that time I still exercised regularly. I had daily to-do lists with over twenty items, and I still found time to exercise. However, after a few weeks off, due to illness, I stopped exercising. I was not busy by any standards, in fact, my schedule was incredibly light. Despite this free time, I found it hard to find time to exercise. It seemed to get pushed later and later into my schedule until it was gone. How can I explain this odd experience? I believe you have known it. What is the best title of the passage? A) Do You Really Lack Time? B) How Can You Work Efficiently? C) What Makes Your Energy Limited? D) When Should You Do Exercise?
**Answer**
A

*Question*
Qian Xuesen is one of the pioneers of China's space science. As a world-famous expert on aerospace rockets and aerodynamics, he obtained great achievements in the areas of applied mechanics, engineering cybernetics and system engineering and made distinguished contributions to the foundation and development of Chinese aerospace undertaking . He graduated from Shanghai Jiaotong University in 1934, and Qian Xuesen went to the United States to study in MIT, Massachusetts Institute of Technology, one year later. After receiving master's degree in MIT, he went to study in California Institute of Technology and received PhD degrees in both aerospace and mathematics. In 1955, six years after the founding of People's Republic of China, Qian Xuesen returned to his motherland. His return brought China the hope of developing space science and its own missiles. In 1956, Qian Xuesen put forward "Proposal on the Development of China's Aviation Industry for National Defense". With the support from Zhou Enlai, the premier, and marshal Nie Rongzheng, Qian Xuesen began to prepare for the establishment of China's first missile and rocket research and development structure, the Fifth Research Institute of State Ministry of Defense. Henceforth , he has long been in charge of the chief technological research and development of China's missile, rocket and spacecraft. Due to research and development led by Qian Xuesen, China successfully exploded its first atom bomb in 1964. Later, China launched its first man-made satellite, Dong Fang Hong I, to the earth orbit on April 24, 1970, becoming the fifth country in the world to independently launch satellite following the former Union of Soviet Socialist Republics, the USA, France and Japan. The satellite floated around the earth, blaring the song Dong Fang Hong, which has the same name as the satellite. As a _ leading the development of China's aerospace science and technology, Qian Xuesen also provided chances for young scientists. Wang Yongzhi, former chief designer of China's... When did Qian xuesen begin to study in Massachusetts Institute of Technology? A) In 1955. B) In 1935. C) In 1936. D) In 1934.
**Answer**


assistant: B