Polyacetaldehyde
聚乙醛
🗣️ 情景例句
Susan, I understand you're in the toy business. Susan
听说 ，是在玩具业工作。
Sure.
不用谢，当然了。
Everybody will be watching anxiously as the new buildings go up.
大家都将急切地注视着新建筑的建成。