1 menace in the air 的意思是能感觉的到的威胁,this time though 然而这次,可能是说前面几次如何如何,这次与前几次不同的意思.
2 主干是the armed men fired
who stopped them 定语从句
warning bursts of automatic gunfire 现在分词做状语,警告要使用自动步枪
3 The fact of shots were fired or be as a warning
完整句是The fact of shots were fired or the fact of shots be as a warning
无论事实是开火还是作为警告