为什么乙炔瓶要安装回火防止器?
参考答案:
乙炔瓶安装回火防止器,可防止气焊气割时倒流的火焰通过焊割炬烧到乙炔胶管内,甚至烧到乙炔瓶,发生爆炸事故。
巴西通用的语言是[ ]
A.英语
B.法语
C.西班牙语
D.葡萄牙语
There()a basketball match this afternoon.
A.is going to be
B.is going to have
C.is going to is
D.is going to has