A few months ago, millions of people in London heard【B1】______ all over the

A few months ago, millions of people in London heard (36) alarms all over the town. The Emergency services, the Fire Departments, the Police, hospitals, and (37) ambulances stood by, ready to go into action. In railway underground stations, people read (38) 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 could be. In 1236 and in 1663, London was (39) badly flooded. In 1928, people living in Westminster, the heart of London, drowned in floods. And in 1953, one hundred people, living on the eastern edge of the London (40) suburbs were killed, again, in the floods. At last, Greater London (41) Council. took actions to prevent this disaster from happening again. Though a flood wall was built in the 1960s, Londoners still must be prepared for the possible disaster. If it happens, 50 underground stations will be under water. (42) Electricity, gas and phone services will be out of action. Roads will be (43) canals; roads will be rivers. It will be impossible to cross any of (44) the bridges between north and south London. Imagine: London will look like the famous Italian city, Venice. But (45) this Exercise Flood Call didn’t cause panic among Londoners. Most people knew it was just a warning. (46) Nobody would be afraid of it.