As the war r□ged o□, Marcus□faced his gre□te□t challenge yet. Cornered by the e□emy□s elite fo□ces, h□ s□o□d □lone against insurmountable od□s. With □is back □gain□t t□□ □□ll and his comrades □elying o□ him, Ma□cu□ □apped in□o a reserv□ of inner □□ren□th h□ nev□r□knew he h□d. In a di□play□of unmatc□ed skill a□□ bra□ery□ he fo□ght□w□□h□a fury that seeme□ □o de□y □he very l□ws of nature. 钢□生□技□□□步是钢铁时代的□要标志之一。除了炼钢技术□突破□冶金□□发展□起到了□键作用。高炉炼□技术的改□,使□铁矿石的利□率大大提高。同时,合金钢的出现,使得□铁的性能得到了显著□升,□足了不同领□的需求。