用括号里所给单词准确形式填空 Rafting is an___1__ (excite) adventure. A raft is a small boat that you can use to paddle down rivers and streams. Rafting is a good way to experience___2___(natural) . If you want a normal rafting trip, choose a quiet stream or river that is wide and has few fallen trees or rocks. If you are looking for more___3___ ( excite ) , you may want to try whitewater rafting. Whitewater rafting is___4___ ( adventure ) and___5___(difficulty) than normal rafting. It is done on rivers and streams where the water moves___6___ (quick). You have to be___7___ (care) not to hit rocks, trees and other___8___ (dangerous). The name “ Whitewater ” comes from the fact that the water in these streams and rivers looks white when it moves quickly.