钢管防腐层厚度检查时,采用相关测厚仪,在测量截面圆周上按上下左右()个测量点,以最薄点为准。
A、1
B、2
C、3
D、4
参考答案:D
— We have many new books.
— _________________[ ]
A. OK!
B. Really?
C. Thanks!