题目内容：

阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

When Peter Sänger 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.”

Their invention — the City Tree — acts as an air purifier — an interesting 4. (add) to urban trees and green spaces. Rooted in science, air pollution can 5. (eat) by the vertical flat-paneled (平面的) “trees” dotted around cities across Europe, while the “trees” also act as seats for pedestrians. Sänger 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 CityTree 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 CityTree network of 15 brand new units and test it in a 10. (science) way in Berlin's pollution hotspots next year.