Keratan
角质素
🗣️ 情景例句
I know you're building a new factory,
我知道你在兴建一座新工厂，
Would you care to take a seat while I make out a receipt?
请坐一会儿好吗？我给您开个收据。
when the whole animal is sometimes preserved, as in a refrigerator.
有时整个动物像被放在冰箱里一样被保存下来，