砂矿中常见的氧化物矿物有刚玉，（），锡石，磁铁矿。
参考答案：黑钨矿
– I’m thinking about tomorrow’s job interview. I’m afraid I will be too nervous to get the job.
– ____. I’m sure you’ll make it.
A．No problem
B．Good luck
C．Go ahead
D．Cheer up
