单项选择题
A.钎焊 B.压力焊 C.熔化焊 D.电阻焊
A.0.10~0.20 B.0.20~0.30 C.0.30~0.50 D.0.50~1.00
A.40°~50° B.50°~60° C.60°~70° D.70°~80°