Rice is one of the most commonly eaten basic foods around the world.Buying it and cooking it is a daily matter.Yet for many，its presence has been a matter of life and death.It is a main food because it is easy to grow，besides low cost and convenience.A poor community in the developing world may find it difficult to bring in foreign fruits or raise cattle for meat，but it can almost certainly use the land it has in order to grow plenty of rice.

    This was the great achievement of Yuan Longping，who passed away on May 22 this year.A great Chinese scientist，Yuan successfully developed what is known as "hybrid rice" which can produce up a 30% higher output.Yuan Longping was born in the year 1930，a time when China was very different.It was a nation，without modern industry，depending on the rice which they grew.The first few decades （十年） of his life were met with major social events，and a rapidly growing population that made food supply not last all the time.This experience left its mark on Yuan Longping，which made him focus on （关注） farming science and work on his research of hybrid rice.

    His achievement would see the rice supply in China increasing from 56.9 million tons in 1950 to 194.7 million tons by 2017.By 1991，20% of the world's rice output came from hybrid rice，even if only being planted in 10% of fields.

    Always remember，human development begins first with the most basic and sample things，such as developing rice.We should be thankful for scientific thinkers like Yuan.

（1）Why is rice a main food around the world？ 　                         　

（2）What did Yuan develop successfully？ 　                               　

（3）When was Yuan Longping born？ 　                                   　

（4）What made Yuan focus on farming science？ 　                         　

（5）How many tons was the rice supply in China by 2017？