When Peter Sanger and Liang Wu got together, it    1    （strike）them that they must be long-lost friends, Both firm advocates in the fight    2    air pollution, they believe that if you can't measure it, you can't beat it. That's    3     they founded Green City Solutions: "The solution to quantifiably improve city air."

The invention—the City Tree—act as an air purifier-an interesting    4    （add）to urban trees and green spaces. Rooted in science, air pollution can be eaten by the vertical flat-paneled（平面的）"trees"    5    （dot）around cities across Europe, while the "trees" also act as seats for pedestrians Sanger and Wu's vision is for a world in which people in cities can live    6    （healthy）. They long to create living conditions that allow all people around the world to permanently have cleaner air    7    （breathe）.

Using remote technology, the City Tree combines    8    air-purifying feature of moss with remote technology to increase the air flow through the "trees". This allows them to "suck up" and clean more air than normal, and the amount they filter can be increased    9    （depend）on pollution levels at different times of day.

The German green-tech start-up is now funded by the European Commission to set up a City Tree network of 15 brand new units and test it in a    10    （science）way in Berlin's pollution hotspots next year.

When scholars of international relations predict that the 21st century will be a “Chinese century”, they are full of reasons.     1     America remains the only superpower, China is responsible for an important share of global change. Since     2     start of the financial crisis in 2008, for example, China has accounted     3    45% of the gain in world GDP. In 1990 about 750 million Chinese people lived in extreme poverty; today fewer than 10 million do. Its GDP per person, in terms of purchasing-power,     4     (rise) ten times since 1990.

China’s amazing     5     (perform) has greatly affected the world’s economic output. The Economist has worked out a geographic center of the global economy by     6     (take) an average of each country’s latitude and longitude(经纬度),     7     (measure) by its GDP. At the height of America’s control, this point     8     (previous) sat in the north Atlantic. But China has pulled it so far east     9     the global center of economic gravity     10     (be) now in Siberia.

Up to 82 percent of children with healthy mothers are not easy to be obese（肥胖的）, according to research. A mother,     1     has a healthy weight, exercises regularly, eats a healthy diet, doesn’t smoke and only     2    (drink) wine in moderation, is significantly less likely     3    (have)a fat child, scientists say.

And research suggests it could be more to do with nurture(养育)    4     nature, as a mother's lifestyle appears     5    (direct) linked to the health of her child. When both mother and child follow a healthy lifestyle, the risk of obesity     6    (reduce)even more, the study of more than 24,000 children found.

The study examined the medical history and lifestyles of more than 24,000 children aged nine     7     fourteen, born to almost 17,000 women in the US. Researchers looked at the link between overall mother health and likelihood of a child     8    (be) obese.

The mother's health was judged on her height-to-weight ratio(比例), her diet, amount of physical     9    (active), smoking status and how much alcohol she drank. A healthy weight and diet, regular exercise, no smoking and moderate drinking all reduce the chance of a woman having     10     obese child.