In Carlsbad Caverns, there are more than 119 caves, including the main cave with the mile-long Big Room walk inside. The park is set along New Mexico's quiet southern border. Make time to also explore the surrounding Chihuahuan Desert, home to the most diverse collection of cactus (仙人掌)species（物种）in the world's deserts. In summer, visitors can watch half a million Brazilian free-tailed bats fill the evening skies.

　　Tel:575-785-2232

　　Price: ﹩10 per person; kids 15 and under, free

　Channel Islands National Park

　　California

　　Just off the coast of Ventura, the five Pacific Channel Islands offer 160 miles of pristine (原始的)coastline. You can reach the islands by boat or plane. Once there, you can see gray whales, Risso's dolphins and elephant seals while on a whale-watching tour, or search for the rare native species such as island foxes.

　　Tel:805-658-5730

　　Price: free

　Isle Royale National Park

　　Michigan

　　Isle Royale is a 570,000-acre island in the northwest of Michigan's Lake Superior. Each summer, visitors go there by ferry or seaplane to explore the island's 19th-century shipwrecks(沉船), learn about trout and whitefish or paddle the plentiful waterways by boat.

　　Tel:906-482-0984

　　Price: ﹩4 per person; kids 10 and under, free

　Dry Tortugas National Park

　　Florida

　　Dry Tortugas --- a remote island about 70 miles west of Key West and due north of Havana ---- is an ideal place for swimmers. In fact, the majority of the park's 100 square miles are actually underwater. Visitors can take a boat, ferry or seaplane to Dry Tortugas, where they'll discover shipwrecks, sea turtles and nearly 300 types of birds.

　　Tel:305-242-7700

　　Price: ﹩10 per person for seven days; kids 16 and under, free

21. How much should a couple with two little babies pay for Carlsbad Caverns National Park?

A. ﹩40. B. ﹩30.

C. ﹩20. D. ﹩10.

22. Which place is the best choice for someone fond of boating?

A. Florida.

B. Michigan.

C. California.

D. New Mexico.

23. Which park should a swimming lover visit?

A. Isle Royale National Park.

B. Dry Tortugas National Park.

C. Channel Islands National Park.

D. Carlsbad Caverns National Park.

　　To see the world is one thing. To have someone to share it with is another. Indeed, travel becomes more interesting when you have a travel partner. A travel partner can be a close friend, a family member, a pal you've met online, or a business friend.

You can have someone to talk to

Traveling alone is fun, but wouldn't you feel lonely? Having a travel partner can remove the feeling of loneliness. This is especially true if you can get a travel companion who is very familiar