Modern zoos are very different from zoos built fifty years ago. At that time, zoos were places ________(1)people could see animals from many parts of the world. The animals lived in ________(2) with iron bars. The cages were easy to keep clean.________(3), for the animals, the cages were small and impossible to hide in. Although the zoo ________(4) took good care of them, many of the ________(5) did not feel comfortable, and they often became ________(6).
In modern zoos, people can see animals in more ________(7) conditions. The animals are given more freedom in larger places ________(8) they can live more freely as they would in ________(9). Even the appearance of zoos has changed. Trees and grass grow in the cages, and water flows________(10) the places that the animals live in. There are few bars,________(11) there is often a deep ditch(沟), filled with ________(12), which surrounds a space where several________(13) of animals live together as
they would naturally. In an American zoo, the visitor can walk ________(14) a huge special cage that is filled with trees, some small animals and many birds. And it is large enough for all the birds to live ________(15).In a zoo in New York, because of special night ________(16), people can observe certain animals that are ________(17) only at night when most zoos are closed. Some zoos have special places for visitors to ________(18) animals that live in the desert or underwater. Some other zoos have special places for animals that live in cold conditions like the ________(19) from the Arctic.
Modern zoos not only show animals for visitors, but also ________(20) and save rare animals. For this reason, fifty years from now, the grand children of today’s can still be able to enjoy watching these animals.
1.A.that   B. where C. which D. there
2.A.houses      B. rooms C. cages  D. offices
3.A.Therefore B. however     C. So      D. Though
4.A.masters    B. managers    C. keepers      D. trainers
5.A.workers    B. animals      C. bears   D. animals     
6.A.excited     B. angry  C. ill       D. frightened
7.A.natural     B. difficult     C. warm  D. different
8.A.so that      B. and     C. but     D. or
9.A.forest       B. nature C. rivers  D. the water
10.A.in   B. by      C. near    D. through
11.A.instead    B. instead of   C. and     D. or
12.A.stones     B. earth   C. oil      D. water
13.A.sorts       B. families      C. classes D. groups
14.A.by   B. out     C. through      D. in
15.A.happily   B. naturally    C. deeply D. hardly
16.A.moon     B. sign    C. light   D. signal
17.A.live B. active  C. living  D. sleeping
18.A.feel B. touch  C. watch  D. talk to
19.A.snakes    B. monkeys    C. bears   D. tigers
20.A.buy B. keep   C. sell     D. catch