After a long time for many years, he is now _____.

A．sickness for his home

B．sicking for his home

C．illness for his home

D．sick for his home

下列有关热裂缝防止措施的叙述正确的是( )。

A．控制焊缝的化学成分；控制焊接工艺参数

B．焊前烘烤，彻底清理坡口和焊丝表面的油、水、锈、污等，减少扩散氧含量

C．焊前预热、焊后缓冷，进行焊后热处理

D．采取降低焊接应力的工艺措施 ．