求翻译和用法及场合 IT MUST BE DOWN

求翻译和用法及场合 IT MUST BE DOWN what an easy life it must be翻译及分析 must be和must的用法 翻译it must be faith. It must be come true用法对吗? 求大侠翻译一下 It must be a sad story must be的用法和意义 let in/out/off/down 的翻译及用法 should be could be must be will be 的用法及区别 must be的用法 must not be 和 can not be 的用法区别 英语翻译it might be fun 和it must be