on your mettle idiom
UK全力以赴，准备尽最大努力
ready to do something as well as you can in a difficult situation
Both players were on their mettle in the final round. 两名选手在最后一轮中都拼尽了全力。
Cooking for such important people really puts you on your mettle. 为如此重要的人物烹饪真是要拿出看家手艺才行。