(7) __1__is known to all, China is a large country__2__agriculture. Science of farming was first __3__(study) here. Jia Si-xie, living__4__the 6th century AD, was one of the farming pioneers(先驱者). After he finished his work for the government, he spent his time__5__his research into agriculture. He studied__6__to keep seeds, how to improve soil conditions and so on. During the years 533~544, he wrote a book__7__(call) Qi Min Yao Shu,__8__is about both farming and gardening,__9__(include) advice on how to grow green vegetables, how to keep fish in lakes, and so on. It was considered to be__10__important summary of farming knowledge.