目前常用的砂轮有氧化铝和（）两类。
参考答案：碳化硅
-Need the government of Philippines(菲律宾政府)say sorry to China?
-Yes, they_______.Their behavior has deeply hurt Chinese people.
A．must
B．need
C．can
D．may
请说出至少3项站址选择的原则？
