leaving,which,beijing,train,for连词成句

leaving,which,Beijing,is,train,for(连句) take,we,train,may,Beijing,the,to连词成句 连词成句：train us take to let a Beijing train is for this nanjing连词成句 Tom is leaving for Beijing next monday 改为同义句? He's leaving for beijing改为一般现在时的否定句 train,he,to,going,Beijing,is,by（.）连词成句 are many the Beijing Train Station there in people 连词成句 are people there in Beijing Train Station many the 连词成句 leave for they Shenyang Beijing 连词成句 do they for leave beijing when怎么连词成句 They are leaving for Beijing tomorrow.为什么用“are leaving”?