Copolyether
共聚多醚
🗣️ 情景例句
Did they write some bad news?
他们写了什么坏消息吗？
What day is today?
今天星期几？
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。