He must be American等于什么

He must be American等于什么 he must ( )here.《be》 He must be happy! 英语：be的用法 He( )an American. Look:Jack is putting on his hat and coat.He must (be going) out.请问这里的be going能否改成go呢?有什么区别呢?结构must+be+doing/coming/joking等must+do/go/know/have等 He must be fun.何如改成一般疑问句?Must he be fun 还是Is he fun? He must be fun.何如改成一般疑问句?Must he be fun 还是Is he fun? 英语翻译he must be--------- ------------thirty years old He must be verg tired.变反意疑问句? Where is he?He must还是must be on that island.选择题,是选 must 还是 must be.谢谢帮忙! he must be bad.he must be very wise.用either...or连接 The dentist thought he must be very.The dentist thought he must be very ill. He must be ---- when he heard the exciting news He must be ill ,for he isn't here. He coughs _____-(terrible).He must be ill. He must be at home.为什么用be? be so sure he must be Mr.Zhang 改为否定句be so sure he must be Mr.Zhang He must be sleeping.与He must sleep.有什么区别