连铸机使用冷却水有（）。
A、机械闭路水
B、机械开路水
C、机械闭路水和开路水
D、硬水
参考答案：C
—All the isatis root（板蓝根） is sold out!
—People are crazy! experts say there is no use eating isatis root to prevent
H7N9, some people still don’t believe it.
A．Although
B．Unless
C．As a result
D．In order that
为什么净化导气前喷淋甲醇及气提氮先投用半小时以上?
