We don’t think the experiment is ___ failure. At least we have gained ___ experience for future success.

A．the; a

B．a; /

C．a; an

D．the; the

以上哪些材料的焊接接头一般不会产生再热裂纹（）

A.低碳钢

B.低合金高强钢

C.珠光体耐热钢

D.沉淀强化的奥氏体钢