英语完形填空~

Modern zoos are very different from zoos that were built fifty years 46. At that time, zoos were places 47 people could go to see animals from

many parts of the world. The animals lived in cages that were made 48 concrete with iron bars, cages that were easy to keep clean.

49 for the animals, the cages were small and impossible to hide in. The zoo environment was 50 natural. 51 the zoo keepers took good care of

the animals and fed them well, many of the animals did not thrive; they behaved in strange ways, and they often became ill.

In modern zoos, people can see animals in more natural habitats. The animals are given more 52 in large areas so that they can live more 53

as they would in nature. Even the appearance of zoos has changed. Trees and grass grow in the cages, and streams of water flow 54 the

areas 55 animals live in.

46.单选题
A. A. later
B. B. ago
C. C. before