the house could fall down soon if no one does some quick repair work.为什么前面用could?而不是can?如果是虚拟,后面就会用did

tom___(fall)off the house the house could fall down soon if no one does some quick repair work.为什么前面用could?而不是can?如果是虚拟,后面就会用did the plot of The Fall of the House of Usher The house could fall down soon if no one ( )some quick repair worka.has doneb.is doing c.dosed.had done the Fall of the House of Usher的主题 the fall of the house of usher 简介 在线等. The British economy could be facing a worse ride than even the US.里面ride是什么意思语境是少了点,不知道有没有人知道呢?ride的意思 这句话的意思?Mr.XX also said that house prices in Britain could fall by as much as a thir 高中英语简单句变复合句1.YOUcallmetosayyou're not coming,I'll see you at the theatre.2.Several weeks had done by.I realied the painting was missing.3.The house could fall down soon.Noone does some quick repair work.4.The situation is danger with the child____,she could have time relaxingto fall asleepfallen asllepbeing fallen asleepfalling asleep the huose could fall down soon if no one__ some quick repair work He could not fall asleep because he___(not give)out the posters yet 请问Edgar Allan Poe的小说 The Fall of the House of Usher的象征意义?用英语回答What symbolic meanings does the House of Usher embody? 请问Edgar Allan Poe的小说 The Fall of the House of UsheWhat symbolic meanings does the House of Usher embody? 1.This is a flim that could make a boy like me,______ never been to New York,fall in love with the place.A.who haveB.who has2.He had a lot of friends ,only a few of ______ invited to his wedding.A.whomB.themC.whichD.who3.Pointing to the house on ____ the fall of the house of usher简写要200多字就可以.....美国文学课..老师要提问..唉 It's said the prices for house sale ( )(fall) a lot in the past ten months 动词填空. It's said the prices for house sale ( )(fall) a lot in the past ten months 动词填空.. The house may fall down soon if no quick repair work____.A.will be done B.is done