Why do people grow green plants on the houses or tall buildings?
Cities call it concrete jungles(水泥丛林）or green roofs. In many people's minds, cities don't have enough green. Green roofs are great to look at and great for the environment. They also give people fresh food and help people make more money.
Now roof gardens are becoming popular in New York City. Some people plant vegetables and fruit on the roof, such as tomatoes, eggplants, green peppers and watermelons.
" I water my vegetables every morning and sell them in the afternoon , so they are very fresh , "said Zaba, a shopkeeper in New York . In fact, he started planting vegetables and fruit on the roof 15 years ago . Half the food in his shop comes from his roof garden.
Some people even keep bees on their roofs. Kurt has 250 boxes of bees. He says the little bees are good for cities. They can not only pollinate(给……传授花粉）plants, but also clean the city's air . Of course, they can give people honey, too.
