分辨词性I happened to be upstairs one evening I didn’t go downstairsI haven’t been able to be outdoors 这三句话中的upstairs ,downstairs和outdoors 分别是什么词性

分辨词性I happened to be upstairs one evening I didn’t go downstairsI haven’t been able to be outdoors 这三句话中的upstairs ,downstairs和outdoors 分别是什么词性 如何分辨to的词性? I happened to be upstairs at dusk.这里的upstairs是什么词性的?前面有be的.这里的be是助词还是有实义的?如果upstairs还有其他词性,也请帮我造个句好吗? 翻译:I happened to be at the station ,when it happened There happened to be no one in your office when I phoneThere happened to be怎么回事啊` 去掉怎么样 I ________ out when the telephone rangA happen B happened C happen to D happened to be 请说明为什么? 英语名词性从句的几个问题1.—— We haven’t heard from Jane for a long time.—— What do you suppose __________ to her.A.was happening B.to happen C.has happened D.having happened 2.I remember ___________ this used to be a quiet villa 连词成句：came,you,to,happened,out,when,your,be,house,I,to I happened to be sitting next to an established programming writer/guru,这个怎么翻译? I want to be told all( )A.which happen B.which happened C.that had happened D.that had been happened When you called me this morning ,I happened -------a meeting Ato be having B.to have I happened to be out when Linda called me yesterday 这句话有问题没. the old man happened to be on be close to的词性 be able to的词性 There ( )nobody in the room.were just happened being were happened happened to be. Peter was happened to be at home that day.为什么是was happened而不是happened I want to be liked and loved for What I am inside.是什么名词性从句?