[解析]
(1)细节理解题。根据第一段There were green forests and they could find enough to eat.Later,parts of the earth became cold and dry,and the forests there died.Then dinosaurs could not find enough to eat.This must be one reason why dinosaurs died out.(那里有绿色的森林,他们可以找到足够的食物。后来,地球的一部分变得又冷又干,那里的森林也死了。那时恐龙找不到足够的食物。这一定是恐龙灭绝的原因之一。)可知,恐龙在几百万年前确实存在于地球上。故选B。
(2)细节理解题。根据第一段There were green forests and they could find enough to eat.Later,parts of the earth became cold and dry,and the forests there died.Then dinosaurs could not find enough to eat.This must be one reason why dinosaurs died out.(那里有绿色的森林,他们可以找到足够的食物。后来,地球的一部分变得又冷又干,那里的森林也死了。那时恐龙找不到足够的食物。这一定是恐龙灭绝的原因之一。)可知,恐龙灭绝的一个原因是缺乏食物,故选D。
(3)细节理解题。根据第三段There may be other reasons that we don't know about yet.Scientists are trying to make more discoveries about dinosaurs.(可能还有其他我们还不知道的原因。科学家们正试图对恐龙有更多的发现。)可知,恐龙值得进一步研究。故选C。
(4)细节理解题。根据最后一段Though there was no man to see any of the fights,we can be told by the footprints (足迹) that fights did take place.(虽然没有人看到打斗,但我们可以从脚印上得知打斗确实发生过。)可知,那些可怕的打斗可以用脚印来解释。故选A。