题目内容
Some caves are open for visitors. Guides take people downstairs to go into the (51) c . Then they (52) g people on paths under the ground. The paths are lighted. As the people walk through,the guides tell (53) h the caves were formed.
Some people would rather see a wild cave. Wild caves (54) d have stairs or lights. People who know how to go into wild caves are (55) c cavers. They take classes to learn how to go (56) t the caves safely. Wild caves can be very
d (57) . Some parts may be underwater. Other parts may have very low roofs.
At Carlsbad Caverns people can go into a cave that is almost (58) w . It is called
a new cave. There are stairs at the start. (59) B there are no bright lights or paved paths. People take their own flashlights,they (60) f a guide along paths marked with red tape.
51. caves 52. guide 53. how 54. don't 55. called 56. through 57. dangerous 58. wild 59. But 60. follow