Polyacetals
聚缩醛(树脂)
🗣️ 情景例句
Shells she sells on the seashore are seashells I am sure.
我敢肯定她在海边卖的贝壳是海贝。
He's a composer of folk ballads.I like his music a lot.
他是民谣歌曲作曲家，我很喜欢他的音乐。
when the plane suddenly turned round and flew back to the airport.
这时飞机突然调转头来，飞回了机场。