Geogen
地理环境因素
🗣️ 情景例句
Joan?
是简吗？
When I left, he was at home.
当我离开的时候，他回家了。
Once the oxygen content of the air had risen to 25% it was ready to burn.
一旦氧气在空气中的含量达到25%，它就要燃烧。