阅读理解

    Against the assumption that forest fires in Alaska, Canada and Siberia warm the climate, scientists have discovered that cooling may occur in areas where burnt trees allow more snow to mirror more sunlight into space.

    This finding suggests that taking steps to prevent northern forest fires to limit the release of greenhouse gases may warm the climate in northern regions. Usually large fires destroyed forests in these areas over the past decade. Scientists predict that with climate warming, fires may occur more frequently over next several centuries as a result of a longer fire season. Sunlight taken in by the earth tends to cause warming, while heat mirrored back into space tends to cause cooling.

    This is the first study to analyze all aspects of how northern fires influence climate. Earlier studies by other scientists have suggested that fire in northern regions speed up climate warming because greenhouse gases from burning trees and plants are released into the atmosphere and thus trap heat.

    Scientists found that right after the fire, large amounts of greenhouse gases entered the atmosphere and caused warming. Ozone（臭氧）levels increased, and ash from the fire fell on far-off sea ice, darkening the surface and causing more radiation from the sun to be taken in. The following spring, however, the land within the area of the fire was brighter than before the fire, because fewer trees covered the ground. Snow on the ground mirrored more sunlight back into space, leading to cooling.

    “We need to find out all possible ways to reduce the growth of greenhouse gases in the atmosphere.” Scientists tracked the change in amount of radiation entering and leaving the climate system as a result of the fire, and found a measurement closely related to the global air temperature. Typically, fire in northern regions occurs in the same area every 80 to 150 years. Scientists, however, found that when fire occurs more frequently, more radiation is lost from the earth and cooling results. Specifically, they determined when fire returns 20 years earlier than predicated, 0.5 watts per square meter of area burned are soaked up by the earth from greenhouse gases, but 0.9 watts per square meter will be sent back into space. The net effect is cooling. Watts are used to measure the rate at which energy is gained or lost from the earth.

阅读理解

    Kunta wondered why the white people had done this to him. Born a free man, he was now in chains. Heavy iron chains around his feet and hands were fixed to a metal bar that ran round the hall about ten centimeters off the ground. He was just able to lie down on the ground, but could not stand up.

    Kunta had been seized in the forest and then hit on the head with a hard object. When he woke up, his hands and feet had already been tied together. What shocked him most was that the men who carried him were black. He reasoned with them, and tried to persuade them to set him free. But they would not listen to him. When they came to the river, a white man was waiting in the boat for them. There was an argument about money, so it seemed, in a language that Kunta did not understand. Finally, Kunta was thrown into the bottom of the boat and covered with an old smelly cloth. The men took him in their boat to the castle on the coast where he was now held prisoner.

    Another thing which shocked Kunta was that women were held in the castle too. He could hear their crying, also children's voices. What was to become of them all, he wondered. For all his life, he had known that people suddenly disappeared from their villages. He had known that it was not safe to travel alone in the forest near the coast. But why did white people want to catch Africans and put them in chains? Would they be killed or even eaten? The situation seemed hopeless and he knew his life was in danger.

    Worse was to come. A few days later about 140 black people were taken and put on a tall sailing ship waiting off the coast. Once on the boat, they were taken below and their chains were fixed to two bars that ran the length of the ship. Their feet were fixed to one bar and their hands to another bar. Thus they lay on hard wooden boards, unable to stand up or move around.

    The sea journey lasted over sixty days and nights. They had rough weather and Kunta's back bled from rolling over on the hard wooden boards. Many of the men fell sick with fever. They sighed and cried out for more water, but food and water were only given out once a day. Once in a while sailors came down, Kunta thought, to carry sick men upstairs for treatment. When the ship finally arrived in a port, the wooden cover was opened wide and Kunta could see in daylight for the first time across the part of the ship where he had been chained. About a third of the people who had been chained up below at the beginning of the journey were missing.

2013年4月28日,习近平在与劳动模范代表座谈时说道:“‘一勤天下无难事’,必须牢固树立劳动最光荣、劳动最崇高、劳动最伟大、劳动最美丽的观念,让全体人民进一步焕发劳动热情、释放创造潜能,通过劳动创造更加美好的生活。”下列能够体现这一观念的做法是（  ）

①各尽所能,按需分配　②个人消费品实行按劳分配

③在企业内部形成奖勤罚懒的机制　④全面建成覆盖城乡居民的社会保障体系

2013年4月28日,习近平在与劳动模范代表座谈时说道:“‘一勤天下无难事’,必须牢固树立劳动最光荣、劳动最崇高、劳动最伟大、劳动最美丽的观念,让全体人民进一步焕发劳动热情、释放创造潜能,通过劳动创造更加美好的生活。”下列能够体现这一观念的做法是（  ）

①各尽所能,按需分配　②个人消费品实行按劳分配

③在企业内部形成奖勤罚懒的机制　④全面建成覆盖城乡居民的社会保障体系

2013年4月28日,习近平在与劳动模范代表座谈时说道:“‘一勤天下无难事’,必须牢固树立劳动最光荣、劳动最崇高、劳动最伟大、劳动最美丽的观念,让全体人民进一步焕发劳动热情、释放创造潜能,通过劳动创造更加美好的生活。”下列能够体现这一观念的做法是（  ）

①各尽所能,按需分配　②个人消费品实行按劳分配

③在企业内部形成奖勤罚懒的机制　④全面建成覆盖城乡居民的社会保障体系