Cách sử dụng
The expression "of steel" is used when talking about something or someone that is very strong, tough and resilient, like steel. For example, "he has a will of steel" means he has a very strong and determined personality. "The building was made with a frame of steel" means the building had a sturdy and strong structure made of steel. This expression is mostly used in a figurative sense to describe a person's or thing's strength and resilience.