They have visited some 20 cities across china.这句话里的 some 20 cities 是哪种语法现象?

They have just visited our school=They （）visited our school（） 否定句 Either the twins or their father ( )our school before ,so they can come here by themselves tomorrow.(visit)请问应该填has visited 还是have visited 为什么啊,请给我解答一下!谢谢. The Whites have visited many places of interest since they came to Chinese.中为什么要用have visited —Is this the first time you _________Chengdu?—No.But the first time I _________here,the city wasn't so beautifulA.visited; came B.visited; have comeC.have visited; have come D.have visited; came They have done a good job. ..“They have done a good job.” “ .”　A) So they have done B) So they haveC) So have they D) So is it ___________ had enough time,they would have visited the Great Wall.A) Had they B) Have they C) Would they have D) If they The foreigners _____ many places since they came here.A.visited B.have visited C.are visiting D.will visit Is this the movie theater ( )they visited yesterday?1.Is this the movie theater ( ) they visited yesterday?A.what B.there C.which D.the one2.-Do you think our football team will win the match?-Yes ,we have better players .So I ( ) them to win.A.hope Not only Jam but also his parents ___ a few mteresting.place since they came to china.A.will visit B.have visited C.has visited D.visited so they have( )nothing to do now 英语翻译1Children like Disneyland,because()there?A they always have a lot of funsB there are so many funsC there is so much funD they are a lot of funs2How many scenic spots in beijing have you ()?A visit B visit to C visited D visiting so they spend money they don't have 怎么翻译 . so they spend money they don't have 怎么翻译 I'm sure that they must have visited the place before帮忙翻译下. Most of the boys in your class have visited the Shanghai World Financial Centre____?A .do they B.don't they C.have they D.haven't they they are talking about the teathers and schools which they have visited 这句话错在哪里? they have been there before.so have i they have been there before.(),() 改为同义句 The Blacks___many places of interest since they came to china.A will visit B.visited C.visitD.have visited 选哪个?说下为什么