焊接应力按形成的原因分为热应和组织应力凝缩应和()应力和氢致集中应力等五种。
参考答案:拘束
I don't want to imply that every point in this contract ( ) negotiable.
A.are
B.is
C.being
D.been
发动机启动时,备用汇流条由哪里供电?
A、主电瓶
B、重要汇流条
C、备用汇流条