[单选题]以下不属于三爪卡盘的特点是( )。
A.找正方便
B.夹紧力大
C.装夹效率高
D.自动定心好

Every year landslides (滑坡) cause 25 to 50 deaths and $1.5 billion in damage in the United States. 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 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, the 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 robo
A. A human being.
B. A spider.
C. A truck.
D. A drill.