采取较高冶炼强度操作时，保持高炉顺行应采取（）。
A、发展边缘气流
B、发展中心气流
C、造成两条煤气通道
参考答案：C
The scientists are making further research to develop more advanced rockets________spaceships can
be launched.[ ]
A. which
B. with which
C. /
D. with that
什麽是高调？
