例句與造句

1. The air density dependence of the maximum raindrop diameter together with fossil raindrop imprints has been used to constrain the density of the air 2.7 billion years ago.
2. He helped pioneer two techniques : using fossil raindrop imprints to set an upper limit on air density, which was applied to fossil imprints from 2.7 billion years ago, and using fossil bubbles in ancient lava flows, which suggests that air pressure 2.7 billion years ago was less than half that of the modern atmosphere.
3. It's difficult to find fossil raindrop in a sentence. 用fossil raindrop造句挺難的