The resulting steel appears to achieve a combination of strength and toughness that is comparable to that of modern steels that are very rich in alloy content and, therefore, very expensive.
2019年6月六级真题(第三套)阅读 Section A
柯林斯高阶英汉双解学习词典释义
ADJ-GRADED
坚强的;吃苦耐劳的;坚韧不拔的
A tough person is strong and determined, and can tolerate difficulty or suffering.