泰国红宝石内部包裹体的特征是()
A.几乎无金红石
B.有金红石包裹体
C.不含水铝矿包裹体
参考答案:A
— Could you come back home at three o'clock?
— _____. I'll be at a meeting at that time. [ ]
A. I think so
B. Yes, I hope so
C. I'm afraid not
D. I'm afraid so
需求曲线