Giant panda Ya Ya arrived at Shanghai Pudong International Airport on Thursday from Memphis, Tennessee.

Ya Ya returned 【小题1】 China from the United States after a 20-year loan for a joint research and conservation project, according to the National Forestry and Grassland Administration.

In December, the Memphis Zoo 【小题2】(announce) that it would return Ya Ya, who arrived in the US in 2003.

The zoo hosted a farewell party for the 23-year-old female panda on April 8, with hundreds of people 【小题3】(attend) the event, Xinhua News Agency reported.

In January, Chinese netizens showed their concern for Ya Ya, who appeared somewhat malnourished (营养不良) in pictures and videos 【小题4】(post).

In 【小题5】(respond), the Chinese Association of Zoological Gardens said in 【小题6】 announcement that the zoo had taken good care of her, and there is no indication that she was neglected, based on videos of her and the results of 【小题7】(month) health reports and annual physical examinations.

In 2006, Ya Ya began to shed fur, a condition 【小题8】 worsened in 2014. 【小题9】(expert) at the Memphis Zoo and in China tried various forms of treatment but were 【小题10】(able) to resolve the problem, the association said.

Huang Yifan, a student from Shandong Province, 【小题1】(like) observing ants and has discovered many funny secrets behind their behaviors, helping him win the gold medal in the S. -T. Yau High School Science Award, which is aimed to inspire scientific innovations for Chinese high school students all over the world. Since last August, Huang 【小题2】(commit) to the competition. He’ve found that 【小题3】ants live underground for a long time, they could still find out if other ants belong to the same nest. 【小题4】(test) this, Huang made a nest with about 100 ants, using materials such 【小题5】 test tubes and plastic bottles.

He applied blue paint to the stomach of one of the ants and put it back into the nest and observed how the rest of the ants responded. “After the 【小题6】(paint) ant enters the nest, 【小题7】 rest will attack it and stop it from entering the nest. But when the ants discover that the dyed ant comes from the same nest by using their eyes and sense of smell, they will stop attacking, ” Huang said.

With animal tracking software, cameras and other instruments, Huang designed six experiments to 【小题8】(far) explore the individual ants’ ability to recognize their nestmates. “Social insects like ants and bees have a strong【小题9】(able) to distinguish their own nest- mates, 【小题10】 helps to enhance the cohesion (凝聚力) within the nest,” Huang added.

All scientists subscribe to the view 【小题1】 the increase in the earth’s temperature is due to the burning of fossil fuels like coal, natural gas and oil to produce energy. Some byproducts of this process【小题2】 (call) “greenhouse” gases, the most important one of   【小题3】 is carbon dioxide. Dr Janice Foster explains: “There 【小题4】 (be) a natural phenomenon that scientists call the “greenhouse effect”. This is when small amounts of gases in the atmosphere, like carbon dioxide, methane and water vapour, trap heat from 【小题5】 sun and therefore warm the earth. 【小题6】the “greenhouse effect”, the earth would be about thirty-three degrees Celsius 【小题7】(cool) than it is. So, we need those gases. The problem begins when we add huge 【小题8】 (quantity) of extra carbon dioxide into the atmosphere. 【小题9】means that more heat energy tends to be trapped in the atmosphere 【小题10】(cause) the global temperature to go up.”