The Wu family moved to Vancouver, Canada in the early 1990s. As they were living in an English-speaking region of the country and hoped to ___36___ themselves more quickly to the new environment, they made up their mind by stopping using their native language and speaking only English at home. However, when the Wu children grew up and went back to their home country, China, the children had difficulty communicating with relatives there. At that time, they realized that it was a ___37___ for them not to make their children become bilingual. Linguistically speaking,the most ___38___ advantage of being bilingual is that those people will be able to communicate with more people around the world. They are more autonomous and do not need to rely on other people to understand other languages.Apart from this linguistic benefit, bilingual people have got the ___ 39___ over other people because they have a higher level of cultural and social awareness of another group of people. Knowing the vocabulary, idiomatic expressions, and even jokes of another language enhances people’s understanding of another culture. One more advantage of being bilingual is that people can gain global awareness. Different regions of the world can be more closely connected if mutual understanding between people of different nations can be achieved. ___40___ , lack of the ability to speak a second or third language can only result in miscommunication and even hostility among people. Since bilingualism offers people many assets at their disposal, it is always wise to learn to speak a second or third language.

With his high G.P.A., nearly perfect SAT score and activities — debate team, tennis captain and state orchestra — Mr. Jia believes he should have had a fair shot at Harvard, Princeton, Columbia and the University of Pennsylvania. However, those Ivy League colleges rejected him after he applied in the fall of 2015. 

It was particularly disturbing, Mr. Jia said, when classmates with lower scores than his — but who were not Asian-American, like him — were admitted to those Ivy League institutions. 

“My gut reaction was that I was super disillusioned by how the whole system was set up,” Mr. Jia, said. 

Students like Mr. Jia are now the subject of a lawsuit accusing Harvard of discriminating against Asian-Americans in admissions by imposing a penalty for their high achievement and giving preferences to other racial minorities.

     Throughout its long history, Earth has warmed and cooled time and again. Climate has changed when the planet received more or less sunlight due to subtle shifts in its orbit, as the atmosphere or surface changed, or when the Sun’s energy varied. 

     Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century primarily due to the greenhouse gases released as people burn fossil fuels. The global average surface temperature rose 0.6 to 0.9 degrees Celsius (1.1 to 1.6°F) between 1906 and 2005, and the rate of temperature increase has nearly doubled in the last 50 years. Temperatures are certain to go up further. 

     Earth’s temperature begins with the Sun. Roughly 30 percent of incoming sunlight is reflected back into space by bright surfaces like clouds and ice. Of the remaining 70 percent, most is absorbed by the land and ocean, and the rest is absorbed by the atmosphere. The absorbed solar energy heats our planet. As the rocks, the air, and the seas warm, they radiate “heat” energy (thermal infrared radiation). From the surface, this energy travels into the atmosphere where much of it is absorbed by water vapor and long-lived greenhouse gases such as carbon dioxide and methane. When they absorb the energy radiating from Earth’s surface, microscopic water or greenhouse gas molecules turn into tiny heaters— like the bricks in a fireplace, they radiate heat even after the fire goes out. They radiate in all directions. The energy that radiates back toward Earth heats both the lower atmosphere and the surface, enhancing the heating they get from direct sunlight. This absorption and radiation of heat by the atmosphere—the natural greenhouse effect—is beneficial for life on Earth. If there were no greenhouse effect, the Earth’s average surface temperature would be a very chilly -18°C (0°F) instead of the comfortable 15°C (59°F) that it is today. 

     What has scientists concerned now is that over the past 250 years, humans have been artificially raising the concentration of greenhouse gases in the atmosphere at an ever-increasing rate, mostly by burning fossil fuels, but also from cutting down carbon-absorbing forests. Since the Industrial Revolution began in about 1750, carbon dioxide levels have increased nearly 38 percent as of 2009 and methane levels have increased 148 percent. The atmosphere today contains more greenhouse gas molecules, so more of the infrared energy emitted by the surface ends up being absorbed by the atmosphere. Since some of the extra energy from a warmer atmosphere radiates back down to the surface, Earth’s surface temperature rises.