There are a lot of _____ in our school. They work very hard.[ ]

A. woman teachers                    

B. women teachers

C. womans teachers                  

D. women teacher

连铸开浇堵引锭头的主要目的是（）。

A．保温

B．防止二次氧化

C．防止开浇漏钢

D．保护引锭头