单项选择题
Which of the following nondestructive testing methods can be used to detect a suspected subsurface defect in a tail-shaft liner?（）
A.Dye penetrant B.Magnetic particle C.Ultrasonic D.All of the above
单项选择题 To anneal a copper gasket, you should heat the gasket（）
单项选择题 A drilled hole is accurately finished to size with a （）
单项选择题 Which of the files listed is tapered on three sides and is used to file acute internal angles?（）
