Another way of growing fresh food is to build urban farms on rooftops. This more practical approach may be more achievable than the idea of farms in skyscrapers, researchers suggest. Experts agree that innovative (革新的) farming practices are needed to support the need for more food at affordable costs, both to the farmer and to the consumer, but the best ideas have yet to come.

体裁：议论文　题材：科普知识　主题：城市垂直农业

【语篇解读】　本文是一篇议论文，提出传统农业所提供的食物满足不了日益增长的人口的需求，垂直农业或许可以解决这一问题。但对这一农业方式，不同的人有不同的看法。

9．What primary problem could vertical farming settle?

A．Poor state of rural life.

B．Shortage of food supply.

C．High cost of transporting crops.

D．Environmental pollution by traditional farming.

答案与解析：B　考查细节理解。根据第二段中的“If current farming practices don't change, we will need an area of new land to produce enough food for the planet.”及第三段中的“Vertical farms... could be the solution.”可知，如果现代的农耕方式不改变，我们将需要新的土地来为地球(上的人们)生产足够的食物，而垂直农业或许可以解决食物短缺问题，故选B项。