哪个城市被称做“草原钢城”？（）A．呼和浩特 B．包头 C．赤峰 D．呼伦贝尔

This agreement will be signed by the managers_________. [ ]

A. concerns

B. concerning

C. concerned

D. to be concerned

( )在债券存续期内其票面利率保持不变。

A．零息债券

B．浮动利率债券

C．息票累积债券

D．固定利率债券

He's been dead for 5 years, ______? [ ]

A．isn't he

B．wasn't he

C．didn't he

D．hasn't he

锚杆的基本类型有（）。

A.圆柱形、扩大圆柱形、缩小圆柱形

B.圆柱形、扩大圆柱形、圆锥形

C.圆柱形、缩小圆柱形、圆锥形

D.圆柱形、扩大圆柱形、圆锥形扩大

蒸汽管道上选择（）色手轮的阀门。

A.红色

B.黑色

C.蓝色