某厂的精矿产率为5.0％，求该厂的选矿比?
参考答案：
该厂的选矿比为20。
Many people felt it was a pity that the ancient tower was and a modern building was being built. [ ]
A.pulled off
B.pulled down
C.pulled up
D.pulled in
1886年国际语音学会成立，被看成是（）成熟的标志。
A、直接法
B、认知法
C、功能法
D、语法一翻译法
