常用于制造电线、电缆的金属是( )
A.铁
B.铜
C.锌
D.镁
在金属中,导电性最好的是银,铜次之.故选B
China has a growing number of middle-class parents who _____ for years to get their only child into a top school.
A.had been saved
B.have saved
C.had saved
D.have been saved
新闻稿的结构有哪几种常见的形式()。
A.金字塔式结构
B.倒金字塔式结构
C.并列结构
D.顺时结构