【正确答案】
B
【答案解析】[听力原文] A few months ago, millions of people in London heard alarms all over the city. The emergency services, the Fire Departments, the police, hospitals, and ambulances stood by, ready to go into action. In railway and underground stations, people read notices and maps which told them where to go and what to do in the emergency. This was Exercise Flood Call, to prepare people for a flood emergency. London wasn't flooded yet, but it is possible that it will be. Though a flood wall was built in the 1960s, Londoners still must be prepared for a possible disaster. If one happens, 50 underground stations will be under water. Electricity, gas and phone services will be out of action. Roads will be drowned. It will be impossible to cross any of the bridges between north and south London. What happened in London a few months ago? 利用播放答题导语的时间，快速浏览每道小题的四个选项。由选项关键词London，flooded，emergency exercise，bridges，collapsed，flood wall，rescue teams，alarm system和waterproof可以判断该则新闻与伦敦和洪水有关。 四个选项均叙述过去发生的一件事，可判断本题以what提问，听到问题后立刻回忆所听新闻内容，结合选项作答。 新闻开头描述了一幅紧张的画面，随后对此进行了说明，这是一次防洪演习警报，帮助人们做好防洪应急准备(This was Exercise Flood Call，to prepare people for a flood emergency)，因此B正确。