【推荐1】When your child is supposed to be doing homework, are they chatting with their friends on Facebook or playing games? Many studies have shown that multitasking doesn’t_______, _______your child is probably proudly claiming they can do ten things_______! Many people believe that they can_______two or more tasks at the same time, but Dr. Edward Hallowell says this is_______. The reality is that multitasking_______poor job performance.

New hand-held_______such as smartphones, iPads, games and social networking sites make it very easy to multitask and “attention_______” leading to difficulty focusing on the task_______, such as listening in the classroom or doing homework. “__________, the brain actually__________kids for multitasking even though when your child is supposed to doing homework performance on every task gets worse and worse. Kids don't know that they are doing__________because they feel better when they multitask,” says Dr Edward Hallowell.

__________the appearance of hand-held devices and social networking sites, teachers have noticed a difference in__________performance, critical thinking skills and how information is__________. “Multitasking prevents people from gaining a deep understanding of the information they are trying to learn,” says Dr Edward Hallowell. Kids have a difficult time sticking with a” difficult to understand" topic and__________to allow themselves to be distracted(分散的), to tune out and switch__________ to Facebook or using their cell phones__________working harder at understanding a difficult subject or problem. In the long__________, multitasking affects grades. One study showed that kids that use the Internet while in class did__________on tests resulting in lower grades.

【推荐2】Young children across the globe enjoy playing games of hide and seek. For them, there’s something highly exciting about _______someone else’s glance and making oneself unable to be seen.

However, we all witness that preschool children are remarkably _______ at hiding. They often cover only their eyes with their hands, leaving the rest of their bodies _______.

For a long time, this ineffective hiding method was _______ as evidence that children are hopelessly “egocentric”(自我中心的)creatures.But our surprising research results in child developmental psychology _______ that idea.

We brought young children aged 2-4 into our Minds in Development Lab at USC. Each _______sat down with an adult who covered her own eyes or_______We then asked the child if she could _______ or hear the adult. Surprisingly, children replied that they couldn’t. The same thing happened when the adult covered her own mouth: Now children said that they couldn’t _______ to her.

A number of ________ ruled out that the children misunderstood what they were being asked. The results were clear: Our young subjects comprehended the questions and knew exactly what was asked of them. Their ________ to the questions reflected their true ________ that “I can see you only if you can see me, too.” They simply ________ mutual (相互的) recognition and regard. Our ________ suggest when a child “hides” by putting a blanket over her head, it is not a result of egocentrism. In fact, children consider this method ________ when others use it.

【推荐1】Promising Vaccine Trials Bring Hope To Coronavirus-Weary World

On December 1, 2020, the United Kingdom became the first western country to give emergency ______ for a COVID-19 vaccine. The Medicines and Healthcare Products Regulatory Agency (MHRA) officials announced they would begin _______ 800,000 doses of Pfizer’s coronavirus vaccine to 50 British hospitals as early as next week. The initial vaccines will be administered to some of the nation's most ______ citizens — nursing home residents, health workers, and the elderly.

The vaccines are made using a synthetic Messenger ribonucleic acid (核糖核酸), or mRNA, that contains ______ about the coronavirus’s signature spike protein (突刺蛋白). When injected into the body, it provides the immune system a _______ of what the threat looks like and allows it to prepare the antibodies needed to neutralize the virus if a person gets infected. This is different from traditional vaccines, which _______ the immune system by injecting weakened viruses that cannot reproduce themselves very effectively.

The _____ approach has several advantages. Since it does not use a live virus, there is little danger of the vaccinated person being infected with the coronavirus. mRNA vaccines are also easier and faster to mass-produce.

However, questions about how long the vaccines will provide protection and their _____ across various age groups and ethnicities are yet to be answered. Also, at an expected price of between $15 to $25 per dose, the immunizations will be expensive to extend, especially since each person needs two shots to obtain full ______.

______, Pfizer's BNT162b2 must be stored at a temperature of minus 94 degrees Fahrenheit (-70 degrees Celsius), and once melted, it lasts just five days in regular refrigerators. This means that the countries wishing to use the vaccination will first have to build cold storage _______. Moderna's mRNA-1273 will be a slightly easier choice since it can be stored in a regular medical freezer for up to six months. It also remains ______ in a standard refrigerator for up to a month after melting.

“Today’s emergency use authorization in the U.K. ______ a historic moment in the fight against COVID-19. This authorization is a goal we have been working toward since we first declared that science will win, and we ______ the MHRA for their ability to conduct a careful assessment and take timely action to help protect the people of the U.K.,” Albert Bourla, chairman and CEO of Pfizer, said in a press release.

Pfizer and Moderna are not the only ones competing to find a way to stop the spread of this deadly virus that has brought the world to a halt. With the world's greatest minds working together, there is little doubt that the coronavirus will be eliminated. However, given the extent of its ______, it will take some time. Until then, we must all continue to take the precautions recommended by medical experts.

【推荐2】Trackers on Ice

Just because a scientist puts a GPS tracking collar on a wild polar bear does not mean the animal will willingly keep it on.   _______, these huge collars are purposefully loose so that if one becomes annoying, a bear can _______it. But scientists have now found a way to use signals from the discarded(丢弃的)devices.

“These dropped collars_______would have been considered garbage data,” says Natasha Klappstein, a polar bear researcher at the University of Alberta. She and her colleagues instead used_______from such collars, left on sea ice in Canada's Hudson Bay, to track the ice itself. For their study, published in June in The Cryosphere, the researchers _______twenty collars that sent movement data consistent(与······一致的)with ice drift rather than polar bear _______between 2005 and 2015. The resulting records of how melting ice typically drifts in Hudson Bay are unique; there are no easily _______on-the-ground sensors, and satellite observations often cannot _______capture the motion of small ice sheets.

The team compared the discarded collars' movements with widely used ice-drift modeling data from the U.S. National Snow and Ice Data Center (NSIDC). Collar data indicated that the NSIDC model underestimates the speed at which ice moves around in Hudson Bay--as well as the overall _______of drift. Over the course of several months the model could drift away from an ice sheet's location by a few hundred kilometers, the researchers say.

This means the bears may be working harder, when moving against the direction of the ice, than scientists had   ________ .“Since we're underestimating the speed of drift, we're likely underestimating the energetic effort of polar bears," says Natasha Klappstein. The research reveals________insight (洞悉) into how highly mobile ice moves. As melting increases in coming years, such ice will likely become more ________farther north, in the central Arctic. Scientists had known NSIDC data could underestimate drift speeds, but “any time we can find a data ________,it is a good thing.”

Plus,such data could improve predictions about how oil spills or other pollutants may spread in seas ________ with drifting ice, says Walt Meier, a senior NSIDC research scientist,who was not involved in the study. The findings may even ________future NSIDC models. “It's a really nice data set,” Meier says."And certainly one we’ll take consideration.

【推荐3】Competition is good for businesses. In the world of navigation(导航) systems, however, competition is also a necessity – it may not be wise to rely on foreign systems for positioning and tracking services. Now, ________ remarkable accuracy and reliability, China’s BeiDou system has made its presence felt.

The BeiDou project was set up in 1994. The first BeiDou satellite was not launched until 2000. Now, ________, there are already more than 20 BeiDou satellites in orbit (轨道) . They form a ________ network that provides positioning, navigation and timing services for China and several other Asian countries.

This “home-grown” system is now ________ a major upgrade. Earlier this month, two BeiDou-3 satellites, the first of China’s most powerful ________ of navigation satellites, were launched into space. The launch marks the beginning of the global ________ of the BeiDou navigation system. Over the next three years, China plans to send up 30 more BeiDou-3 satellites; The expanded navigation system will ________ create a network that is able to support military and civilian applications around the world.

Scientists involved in the project said the new system would give civilian users an accuracy of 2.5 meters to five meters, overtaking that of the ________ positioning technologies. BeiDou’s chief designer said the new satellites would be able to _______ which lane a car is using on a motorway and _______ the swing of a building in high winds. It will also be able to guide fire trucks to the nearest water hydrant (消防栓).The Chinese military, meanwhile, will be able to use coded signals for millimeter(毫米)________.

China is only the third country in the world to develop a navigation system on its own, after the United States (GPS) and Russia (GLONASS). Developing BeiDou is a necessity. The system _______ national security by ending a reliance on foreign systems. Moreover, it enhances China’s international reputation for technological ________.

For most of us, the benefits of the new satellite system will be felt in a couple of years when more phones are ________ with BeiDou chips (芯片). Many smartphones today still use GPS and GLONASS. That’ll soon change with the development of BeiDou. One product manager ________ most smartphones to be able to receive BeiDou signals. He says: “In three years’ time, people may still say ‘I’m using GPS’, but in fact, their phone is tune in to BeiDou.”

【推荐3】Goodish News of Climate Change

Emissions of carbon dioxide (related to energy production) have stabilized, for now.

Is it a peak, a stutter or just a brief pause? Time will tell. But whatever it is, on February 11th the International Energy Agency (IEA), an intergovernmental ________ which collects such data, announced that emissions of carbon dioxide in 2019 which were ________ to energy had remained the same (33.3bn tonnes) as the previous year’s.

Energy-related emissions, which include those (produced by electricity generation), heating and transport, ________ more than 70% of the world’s industrial CO₂ pollution. The reason why the emissions remained the same was that there was a(n) ________ in coal use, particularly in rich countries, combined with an increase in the use of renewable power.

As a result of this the CO₂-intensity of electricity generation—a(n) ________ of how much of the gas is emitted per kilowatt hour of petrol produced—fell by nearly 6.5%, to 340 grams of CO₂ per kilowatt hour. It had already been ________, but this is three times the average for the past decade. Such declines more than offset (抵消) the ________ of increased electricity production. The average emission-intensity of power generation in 2019 was “lower than all but the most efficient gas-power plants”, according to the IEA.

This is not the first time energy related emissions have plateaued (保持稳定). Between 2013 and 2016 they hovered around 32.2bn tonnes a year, before rising again in 2017 as the use of coal to ________ developing economies increased. This ________ plateau was accompanied by excited declarations that such emissions had peaked. Similar ________ have been made this week, perhaps also prematurely. Besides changes in coal use, a ________ economy may have played a part and the data show that milder than usual weather caused a perceptible drop in emissions from several countries with large, carbon-hungry economies.

________, the latest data from the Amazon rainforest also make us feel relieved. This, one of the world’s largest woodlands, has acted ________ as an absorbing sponge (海绵) for CO₂ by removing it from the atmosphere through photo-synthesis. Researchers at Brazil’s National Institute for Space Research have shown that a vast part of the south-east of the Amazon, about one fifth of its area, has lost its ________ to absorb the gas and is now a net source of emissions into the atmosphere instead. This land has been widely deforested, so the result is little ________. But it is disappointing.