— How ____ the people in Yunnan?
— Very friendly. [ ]
A. were
B. was
C. is
D. do
答案:A
电力系统波过程持续时间为()。
A.毫秒级
B.微秒级
C.秒级
D.分钟级
高锰钢整铸辙叉,辙叉翼垂直裂纹一条裂纹长度超过()为重伤。
A、40mm
B、50mm
C、60mm
D、80mm