Petscheckite
铌钽铁铀矿
🗣️ 情景例句
OK, Richard. That's terrific.
很好， Richard ，真不错。
He can't decide what to do.
他不能决定做什么。
Experiments have proved that children can be instructed in swimming at a very early age.
实验证明，儿童在很小的时候就可以开始学习游泳。