测试

Farms Appear in Cities

When you hear the word “farm”, you may imagine the countryside with cows and crops. But scientists say the farms of the future could be built in tall buildings in some large cities.
　　It may be difficult to believe, but in fact, the technology for growing crops in doors already exists. Farming in the city is already happening. Some vegetables are already grown in greenhouses. Even the scientists at the South Pole research station can enjoy fresh vegetables they grow in their own greenhouse.
　　Experts say indoor farming solves many problems. First, traditional farming takes up a lot of land. Growing crops in tall buildings — called vertical farming（垂直农业）— can solve the problem. Also, fruits and vegetables grown indoors would not face serious threats from insects and weather.
　　Though vertical farms don’t exist yet, experts have created a plan for recycling in such farms. The water from indoor fish ponds would be used to water crops. Gases from crop waste would be used to heat the building. Waste from chicken or pigs would be reused as a source of energy.
　　But experts believe vertical farming is not going to be easy. They say it can be difficult to control climate conditions indoors. Besides, Plants differ in their weather and lighting needs. For example, some plants like warm, sunny weather, but other plants prefer cooler temperatures.
　　That’s not to say these difficulties won’t be overcome — but it will take time. Most experts suggest it may take about 5 to 15 years before the first vertical farms could be created.

总评：这篇作文展示了关于城市中的垂直农业的全面概述。文章结构清晰，内容完整，涵盖了城市农业的现状、优点以及挑战。语言运用较为准确，没有显著影响理解的语法错误，因此，该作文可以被评为第二档，得分应在19到24之间。

存在的问题及修改建议：

1. 拼写错误：“in doors” 应为 “indoors”。

原句：It may be difficult to believe, but in fact, the technology for growing crops in doors already exists.

修改后：It may be difficult to believe, but in fact, the technology for growing crops indoors already exists.

2. 语法和表达上的细微问题：句子“Though vertical farms don’t exist yet, experts have created a plan for recycling in such farms.”可以更清楚地表达主旨。

原句：Though vertical farms don’t exist yet, experts have created a plan for recycling in such farms.

修改后：Although vertical farms have not been constructed yet, experts have developed a recycling plan that could be used in these farms.

经过以上修改后，文章能够更加准确地表达意思而不影响理解。因此，综合考虑文章内容的完整性和语言运用的准确性，给予该作文22分。