Fluorbaryt
荧石
🗣️ 情景例句
Yes, it is. Come up.
是的 是我。请上来
What time does the first train to Boston leave?
第一班去波士顿的列车什么时间开出呢？
it has to develop (partly by means of touch) the ability to judge roughly three-dimensonal distances.
儿童必须发展（部分通过触觉）粗略判断三维空间距离的能力。