Ildefonsite
钽铁矿
🗣️ 情景例句
I really have to go.
我真的得走了。
Do you often play bridge on Saturday?
你常常在星期六玩桥牌吗？
and a period (which is the time it takes a wave crest to travel one wave length).
和周期（浪峰走过一个波长所需的时间）。