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Unlike modern animal scientists, dinosaur scientists cannot sit on a hillside and use telescopes to watch dinosaurs in order to know how they lived and whether they were good parents. Instead, they have to search hard for information from dinosaurs’ fossils (恐龙化石) because dinosaurs died out millions of years ago.
It’s very difficult for the scientists to reach an agreement because different results can be got from the same fossils. Many fossils of the same kind of dinosaurs have been dug out from one place. They might have formed when an entire group of dinosaurs got stuck (陷入) all at once, or they might have been the result of dinosaurs getting stuck one after another over a course of a few centuries. Thus we can say that dinosaurs might have in the first case lived in big groups and in the second lived alone.
