重介质旋流器溢流口直径越大,实际分离密度越大,精煤产率()
A、越大
B、越小
C、不变
参考答案:A
下列物质中,能作磷肥的是
A.Ca(H2PO4)2
B.NH4HCO3
C.K2CO3
D.CO(NH2)2
In Grammar-Translation Method, ______ is maintained as the reference system in the learning of the second language.
A.the first language
B.the second language
C.the target language
D.the foreign language