天然宝石
参考答案：
指天然矿物单晶，矿物是由地质作用形成通常称为固体的无机晶质材料也有有机的琥珀及非晶质材料欧泊，天然玻璃。
Nice to meet you, ___________.[ ]
A. to
B. too
C. /
These shoes _____ new and that pair of shoes _____ old. [ ]
A. are; are
B. are; is
C. is; is
D. is; are
