Stepping into a pool of water is common enough ,but who could ever imagine ; stopping into a pool of fish? In February of 1974, Bill Tapp ,an Australian farmer,saw a rain of fish that covered his farm .How surprised he must have been when he heard many fish hitting against his roof!    What caused this strange occurrence ?This is a question that had long puzzled people who study fish .The answer turned out to be a combination of wind and storm.    When it is spring in the northern part of the world ,it is fall in Australia, Throughout the autumn season ,terrible storms arise and rains flood the land .The strong winds sweep over Australia like huge vacuum cleaners, collecting seaweed ,pieces of wood ,and even schools of fish .Strong winds may carry these bits of nature for many miles before vacuum dropping them on fields, houses ,and stonishedpeople.    Although they seem unusual ,fish-falls occur quite frequently in Australia.When Bill Tapp was asked to describe the scene of fish ,he remarked, "They look like millions of dead birds falling down." His statement is not surprising .The wonders of the natural world are as common as rain .Nature ,with its infinite wonders ,can create waterfalls that flow upward and fish that fall out of the sky. It is a known fact that  _  .
one should watch where one steps Bill Tapp is a scientist who studies farming the natural world can never create waterfalls that fall upward the seasons in the southern part are different from those in the north
Question: Stepping into a pool of water is common enough ,but who could ever imagine ; stopping into a pool of fish? In February of 1974, Bill Tapp ,an Australian farmer,saw a rain of fish that covered his farm .How surprised he must have been when he heard many fish hitting against his roof!    What caused this strange occurrence ?This is a question that had long puzzled people who study fish .The answer turned out to be a combination of wind and storm.    When it is spring in the northern part of the world ,it is fall in Australia, Throughout the autumn season ,terrible storms arise and rains flood the land .The strong winds sweep over Australia like huge vacuum cleaners, collecting seaweed ,pieces of wood ,and even schools of fish .Strong winds may carry these bits of nature for many miles before vacuum dropping them on fields, houses ,and stonishedpeople.    Although they seem unusual ,fish-falls occur quite frequently in Australia.When Bill Tapp was asked to describe the scene of fish ,he remarked, "They look like millions of dead birds falling down." His statement is not surprising .The wonders of the natural world are as common as rain .Nature ,with its infinite wonders ,can create waterfalls that flow upward and fish that fall out of the sky. It is a known fact that  _  .
A. one should watch where one steps
B. Bill Tapp is a scientist who studies farming
C. the natural world can never create waterfalls that fall upward
D. the seasons in the southern part are different from those in the north
Answer: