下列物质属于碱性熔剂的是()。
A.石英
B.Al2O3
C.白云石
参考答案:C
We should bear in mind that social development and balance of nature should go in ________. [ ]
A. company
B. sympathy
C. association
D. harmony
Maybe you could __________ [ ]
A. call up him
B. call him up
C. called him up
D. calling up him