China is a large country of agriculture.We all know that there are more than 800 million 41 in China.China starts to 42 the science of agriculture much earlier 43 other countries in the world.44 people in Europe and America were trying to shoot wild animals and birds for food,farmers in China were 45 the science of agriculture.For example,Jia Sixie,who lived in the Northern Wei period (386-534AD),46 one of the farming pioneers.After he finished his work in government,he 47 home and spent his time on research into agriculture.He 48 information,did experiments and learnt from the experience of farmers.He wrote a book called Qi Min Yao Shu.The book 49 has 110,000 words is about both farming and gardening.This book is 50 to be an important summary (概要) of the knowledge of farming.41.A.workers B.farmers C.pioneers D.scientists 42.A.develop B.grow C.choose D.interest 43.A.to B.till C.then D.than 44.A.Where B.For C.While D.Because 45.A.trying B.working C.studying D.growing 46.A.were B.was C.came D.be 47.A.left B.built C.returned D.destroyed 48.A.advised B.improved C.collected D.planted 49.A.who B.whom C.it D.which 50.A.made B.considered C.kept D.studied