Chemical pesticides and artificial fertilisers have been in widespread use in farming since the middle of the 20th century. When they were first introduced, many farmers welcomed them as a great way to fight crop disease and increase production. Over time, however, what some scientists have found is that their long-term use can sometimes harm both the land and people’s health. 答案：自20世纪中期以来，化学农药和人工化肥在耕作中得到了广泛使用。当它们第一次被引进时，很多农民喜欢使用农药和化肥，把它们作为防治农作物病虫害和提高产量的重要手段。然而，随着时间的推移，一些科学家发现长期使用农药和化肥会造成土地受损，对人们的健康造成危害。