在检验时使用下列哪一种材料做标记,发动机热部件可能会发生裂纹()
(1)铅笔
(2)粉笔
(3)划线染料
A.(1)
B.(2)
C.(3)
D.(1)(2)(3)中任何一种
参考答案:A
— Hello, Sandy. This is Jack. What are you doing?
— I'm watching a match. It started at 7 p.m. and _____ on for another half an hour. [ ]
A. has been
B. was
C. had been
D. will be
Ⅰ度松动牙松动幅度不超过()
A.0.5mm
B.1.0mm
C.1.5mm
D.2.0mm
E.3.0mm