Osteogenin
成骨素
🗣️ 情景例句
A credit card is very useful when you go traveling.
当然旅游的时候，信用卡很有用。
I would like to place a station-to-station call.
我要打一个叫号电话。
Why? One difficulty is to construct the agreements.
为什么呢？困难之一是起草这些协议。