• A. createdD. suburbsG. conditionsJ. M. noise
• B. sufficientE. retainH. fierce K. sequence N. pollution
• C. conductedF. earthI. environment L. local O. permanent
  One thing the tour books don’t tell you about London is that 2,000 of its residents are foxes. They ran away from the city about two centuries ago after developers and pollution moved in. But now that the (1) is cleaner, the foxes have come home.
  "The number and variety of wild animals in (2) areas is increasing, " says Gomer Jones. A survey of the wildlife in New York’s Central Park last year counted 14 species of mammals. A similar survey (3) in the 1890s counted only five species.
  Several changes have brought wild animals to the cities. Foremost is that air and water quality in many cities have improved as a result of the 1970s (4) -control efforts. Meanwhile, rural areas have been built up, leaving many animals on the edges of (5) . In addition, wildlife refuges have been (6) . The Greater London Council last year spent 750,000 to buy land and build 10 (7) wildlife refuges in the city. As a result, many birds are now living in the city. For peregrine falcons (游隼) cities are actually safer than rural cliff dwellings.
  Cities can attract wild animals without turning them harmful. The trick is to create habitats where they can be self- (8) but still be seen and appreciated.
  Such habitats can even be functional. In San Francisco, the (9) government is testing different kinds of rainwater-control basins to see not only which ones (10) the cleanest water but which will attract the most birds.