sth terrible must be happen here为什么不用terribly?

sth terrible must be happen here为什么不用terribly? He coughs _____-(terrible).He must be ill. Attentions must be paid to do sth还是doing sth it must be terrible to be grown up句中to可以不要吗 it must be terrible be grown up 新概念英语第二册lesson17求解it must be terrible to be grown up 为什么用被动语态不是it must be terrible to be grow up呢 It must be terrible to be grown up!这句话里为什么要加be呢? it must be terrible to be grown up中to be 是个什么成分啊? It must be terrible to be grown up.must是情态动词,后面应该+动词原形,be terrible是动词原型?不是的话是什么? It must be terrible to be grown up!grown up与grow up有什么区别 it must be terrible to be grown up 中的grown up 什么词性 Be a must to sth 有这种用法? Darling ,it must be terrible to be grown up .句中为什么to be ,to be ,有什么作用 the old lady must be sent to hospital at once because she was___(terrible) ill ‘Darling,it must be terrible to be grown up '请问：grown up前面为什么有个be, it must be terrible to be grown up!be的作用两个be有什么用,我没学过语法 帮忙分析下面两个英语句子结构I knew that my turn had comeIt must terrible to be grown up it must be terrible tobe grown up请帮我分析一下这句的语法结构 It must be taken actions to do sth.和 Actions must be taken to do sth.的区别这两个意思是不是一样的？