钢: steel...
诀别: to bid farewell, to part (usually with little hope of meeting again)...
使者: emissary, envoy...
考虑: to think over, to consider, consideration...
简单: simple, not complicated...
城墙: city wall...
复制: to duplicate, to make a copy of, to copy, to reproduce, to clone...
苦练: to train hard, to practice diligently, hard work, blood, sweat, and tears...
互动: to interact, interactive...
卷子: test paper, examination paper...
