Every year landslides (滑坡) cause 25 to 50 deaths and ＄1.5 billion in damage in the U. S. They account for 15 percent of the deaths from natural disasters in Europe. And in December, a single event killed more than 200 people in the Philippines. Sending workers to stabilize (加固) mountainsides using steel bars and cement (水泥) can help prevent disaster, but it introduces new difficulties. Shaking drills produce harmful dust and loosen heavy, dangerous debris (岩屑).
"It's quite a risky job," says Giorgio Pezzuto of D'Appolonia, an engineering company in Italy.
D'Appolonia, working with eight other companies, may have an answer: a three-ton robot called Roboclimber. "The idea is to operate a machine far away that can drill without a human being on board," says Pezzuto, manager for the project, which is supported by the European Commission. Engineers claim that the machine will be faster and cheaper than manual labor. The robot, a large radio-controlled four-legged mechanical spider, has cost at least ＄2 million so far. The final product should be able to climb unstable mountainsides, drill holes, insert bars and cement, and collect data on the slope's stability. Testing should begin in May.
The underlined word "event" in the first paragraph refers to______.

A. landslide
B. machine
C. earthquake
D. flood