题目

Thomas Edison lit up the world with his invention of the electric light. Without him, the world might still be in the dark. However, the electric light was not his only invention. He also invented the motion picture camera and 1200 other things. About every two weeks he created something new.Thomas Edison was born in 1847. He attended school for only three months. His mother taught him at home, but Thomas was mostly self-educated. He started experimenting at a young age.When he was 12 years old, he got his first job. He became a newsboy on a train. He did experiments on the train in his spare 下列关于农业投入——产出的叙述，正确的是 ①动植物（或种子）以及自然条件是农业必要的投入 ②农业机械的投入可提高劳动生产率 ③化肥、农药等的投入，可促进农业的产出 ④加大科技投入是提高农业产出的重要手段 [　　] A．①②B．②③ C．③④D．①②③④