压力钢管一类焊缝的外观质量允许存在深度小于等于0.5mm的咬边缺欠。
参考答案：对
----It is nice. Never before___________ such a special drink!
---- I am glad you like it.
A．I have had
B．I had had
C．have I had
D．had I had
轴颈、防尘板座及轮座上存在长度＜25mm，且各部位均不超过（）条的纵向发纹时，可不处理（对其长度不超过4mm的纵向发纹可不计算在内）。
A.3
B.4
C.5
D.6
