名词
中文翻译：初级灭绝
同义词：
['primary event', 'primary crisis例句：1. The primary extinction of the dinosaurs occurred over 65 million years ago.（恐龙的首次灭绝发生在6500万年前。）']
例句：
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1. The primary extinction of the dinosaurs occurred over 65 million years ago.
恐龙的首次灭绝发生在6500万年前。
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2.The primary extinction of the dinosaurs is believed to have been caused by a massive asteroid impact.
恐龙的首次灭绝被认为是由一颗巨大的小行星撞击引起的。
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3. The primary extinction of the dinosaurs had a profound impact on the ecosystem and led to the rise of new species.
恐龙的首次灭绝对生态系统产生了深远的影响，并导致了新物种的出现。