change of temperature hardening change temperature hardening
Related Translations:
锻炼: 1.(体育锻炼) take exercise; have physical training 短语和例子锻炼好身体 build up a strong constitution; 经常锻炼以保持健康 train regularly to keep fit; 热心地从事体育锻炼 pursue one's athletic exercises with zest; 他长期缺乏锻