Polyacetals
聚缩醛(树脂)
🗣️ 情景例句
and they found it to be too easy--
他们发现字太简单了，
Would you mind if I took a day off?
我请一天假可以吗？
Not until last week did I get a work permit.
直到上周我才拿到工作许可证。