果蝇主要以腐烂的水果为食，是遗传学中常用的实验动物．分析回答：

①壮大集体经济，实现农业规模化经营     ②推动以工促农，提高土地资源利用率

③促进土地流转，划分农村土地所有权     ④实现土地增值，促进收入分配多元化

   More than a hundred years ago, an American produced a game. He called it indoor tennis. The Americans were not interested in it at first so he sent it to his London friends and it became very popular in Britain.The game was then played across the dining room table, or on the floor with the net hung between two chairs. The balls were made of cork or rubber.The bats were made of wood.
   A few years later a hollow ball like the one we use today was invented. The game then quickly spread all over the world. An Englishman once made a bat covered with rubber. He first played the game in England and called it “ping-pong”. “Ping”was the sound of the bat when it hit the ball. and “pong” was the sound of the ball when it hit the table.