检查盘条时，表面应光滑，不得有裂纹、折叠、耳子、结疤；盘条（）有夹杂及其它有害缺陷。
A.可以
B.不能
C.允许
D.可带
参考答案：B
I _______ my grandmother.
A．visiting
B．is visiting
C．am visiting
D．Visit
Most propellers on merchant vessels are constructed of（）.
A.managanese bronze
B.cast iron
C.mild steel
D.improved plow steel
