there has been four sets of invaders of english为什么用has?

there has been four sets of invaders of english为什么用has? there _____ (be) four buildings built already in our school.是填have been 还是has been there has been的用法 There has been a misunderstanding. there has been...为什么要加been? 请问这里应该填什么?there ＿＿(be) four buildings built already in our school应该填have been还是has been? 这里应该填什么?there ＿＿ (be) four buildings built already in our school应该是have been还是has been? Mr sun (has been/gone)to japan four times. Sam has been skating for four hours.改为否定句 There have been four sets of invaders of England是什么意思 he has been to China four times还是for four times he has been to england four times 对four times提问 there has/have been的用法 he has been there _twice____.画线提问 We love,difference has always been there. He has never been there.英译汉 The committee_____ among themselves for four hours.A.has been arguing B.have been arguing 翻译:She has never been there,has she?