转化炉火嘴点火时,应()
A、先开燃料气阀,后伸入点火棒
B、先伸入点火棒,后开燃料气阀
C、先点火嘴,后开引风机
D、先全开烟道挡板,后点火嘴
参考答案:B
At first, I found ____ very hard to learn English by myself. [ ]
A. it
B. it's
C. that
D. that's
结构性能检验时,对成批生产的预制构件,应按同一工艺正常生产的不超过1000件且不超过()的同类产品为一批进行检验()。
A.3个月
B.30天
C.2个月
D.15天