19.C根据最后一段可以得出答案。

18.A根据第三、四、五段可以得出答案。

17.D根据第二段中最后三句话可以得出答案。

16.D根据第一段But you must go there yourself to feel its true size and beauty.可知答案。

20. If you want to have a visit to the Grand Canyon, you’d better go to _______.

A. the North Rim　　　　　　　　　 B. the South Rim

C. the bottom　　　　　　　　　　 D. Navado Indian Lands

[答案解析]

19. If you want to visit the North Rim from the South Rim, you________.

A.　 can go there in many directions

B.　 won’t spend much time on the way

C.　 can visit The painted Desert on the way

D.　 needn’t go across any bridges

18. The scene the canyon is ________.

A.　 various depending on different time and places

B.　 the same　　

C.　 various depending on different time

D.　 various depending on different places

17. According to the second paragraph, ________.

A.　　　 the Grand Canyon has a short history　　　

B. its size never changed in the history

C. the Grand Canyon was formed by the earthquake　

D. You can enjoy different scenery on different sides of the canyon

16. The best way to feel the true beauty of the Grand Canyon is to________.

A. see its photographs　　　　　　 B. listen to the report about it

C. watch its introduction on TV　　 D. go there yourself and visit it