| Unless we spend money to spot and
prevent asteroids (小行星) now, one might crash into Earth and destroy life as we
know it, say some scientists. Asteroids are bigger versions of the meteoroids (流星)that race across the night sky. Most orbit the sun far from Earth and don’t threaten us. But there are also thousands whose orbits put them on a collision course with Earth. Buy $ 40 million worth of new telescopes right now. Then spend $10 million a year for the next 25 years to locate most of the space rocks. By the time we spot a fatal one, the scientists say, we’ll have a way to change its course. Some scientists favor pushing asteroids off course with nuclear weapons. But the cost wouldn’t be cheap. Is it worth it Two things experts consider when judging any risk are: 1) How likely the event is; and 2) How bad the consequences if t A. It is very unlikely but the danger exists. B. Such a collision might occur once every 25 years. C. Collisions of smaller asteroids with Earth occur more often than expected. D. It’s still too early to say whether such a collision might occur. 热门试题: [单项选择]发射耦合器是利用电感的（）原理工作的。
A. 互感 B. 通低阻高 C. 通直阻交 D. 自感 [单项选择]胸部摄影，FFD选用180cm的原因是避免因（）
A. 左右径较窄、前后径较薄引起的影像放大 B. 左右径较厚、前后径较宽引起的影像放大 C. 左右径较短、前后径较长引起的影像放大 D. 左右径较扁、前后径较窄引起的影像放大 E. 左右径较宽、前后径较厚引起的影像放大 [单项选择]我国压强的法定单位是（）。
A. mmH2O B. mmHg C. Pa D. at [单项选择]TPC描述正确的是（）
A. 用于内环快速功率控制 B. 每个时隙使用1次 C. 用于外环快速功率控制 D. TPC共3个比特 [不定项选择题]A.绝经期综合征
A.痛经 B.回奶 C.再生障碍性贫血 D.子宫内膜腺癌 E.大剂量雌激素用于 [单选题]下列病原体中青霉素G治疗无效的是
A.革兰阳性球菌 B.革兰阴性球菌 C.革兰阳性杆菌 D.革兰阴性杆菌 E.螺旋体 [单选题]过盈连接的类型有（）和圆锥面过盈连接装配。
A.螺尾圆锥面过盈连接装配 B.普通圆柱销过盈连接装配 C.普通圆锥销过盈连接装配 D.圆柱面过盈连接装配 [简答题]ABC会计师事务所接受委托，承办某公司2009年度财务报表审计业务。A和B注册会计师负责确定与交易、账户余额、列报与披露相关的实质性程序。 要求：针对下表列示的各项认定，请代A和B注册会计师列示出为实现各认定的审计目标应实施的最常用的实质性程序(请将答案直接填入相应表格内)。
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