题目解析:
原文this bolide (either a comet or an asteroid) was traveling at cosmic speeds of 20-70 kilometers per second, or 45,000-156,000 miles per hour.对应B选项。Such a huge mass traveling at such tremendous speeds carries an enormous amount of energy. When the bolide struck this energy was released and generated a huge shock wave.对应C选项。The impact displaced huge volumes of seawater, causing much flood damage in the Caribbean.对应D选项。A选项为什么火流星会落向地球没有在原文中提及,所以选择A选项。