Polyacetals
聚缩醛(树脂)
🗣️ 情景例句
will read a poem by Robert Frost.
要朗读Robert Frost作的一首诗。
The pen is the tougue of the mind.
笔是心之舌。
What do the machines do? asked Jim.
“这些机器做什么用？”吉姆问。