每日背诵第五期60
Dinosaurs were once found all over the earth. Now they are gone. They have all died out. No one is sure how this happened. Some scientists believe the weather changed. Some believe disease killed them all. All that we can be sure of is that once they lived.
恐龙曾遍布地球的每个角落，现在他们没了，全部都灭绝了。没有人确定这是怎么发生的。一些科学家认为气候变了，还有一些认为是疾病导致它们灭绝。我们所能确定的就是它们曾经生存过。
