英语：Could （ ） have been ( )who helped Sunny get her work done?1.they ,it 2.they ,them 3.it ,them 4.it ,they这句话什么情况 我没看明白 4是什么情况?其他的为什么不能用 请帮我分别解释一下好么

They have already read an write填问号（can,could,be able to）适当形式 英语举例子!用下面条件造句most+动原can't+动原正在进行时may+be+v-ingmight+be+v-i过去时态could+have+过去分词could+have+been+过去分词 英语举例子!用下面条件造句most+动原can't+动原正在进行时may+be+v-ingmight+be+v-ing过去时态could+have+过去分词could+have+been+过去分词 英语：should have done与could have done区别? 在英语作文里could be 可以代替can be 高二英语选择：We could have asked someone to carryWe could have asked someone to carry out the plan privatelywithout it _____.A was known B.knows C.being known D.be known请详细说说. 一道英语选择题,请解释it was so quiet in the classroom that a needle _to drop onto the floor A .could hear B .was to be heard C .could have been heard D .must be heard No one could be fatter.No one could have been fatter.意思上有什么不同? if the weather had been more favorable,the crops （）still better1 should have grown2 would be grown3 would be growing4 could be grown If there___no sunlight in the world,we___in darknessA should be;would have livedB could be;would liveC could be;would have livedD should be;would live If you could have any job you wanted,what would it be and why?如题,写一个200字左右的英语文章, will be done和will have done是什么情况could have been呢 英语单选 时态6The days __ longer and we ___ more hours of sunlight in summer .A will be :have B are :will have C will be :will have D are :have7.I could have been on time for the meeting,but I___ in a traffic jam for over half an hour .A have c could have been done ,could have 2011年12月18号湖北省英语三级答案求排除1,subject　　2,in　　3,could be taken.　　4,pay off l　　6,adoptable　　7,Which　　8,will have 　　9,hand and foot　　10,be introduced.　　二,词性转化（转换后）　　1,t 英语选择题（时态的）If we could reflect sunlight back into space by just one percent,global warming ______.A.had to be stopped B.would be stopped C.had been stopped D.would have been stopped还要原因哇! 英语8.“We could have walked to the station as it was so near.”8.“We could have walked to the station as it was so near.”“Yes.A taxi _____at all necessary”A.wasn’t B.hadn’t been C.wouldn’t be D.won’t be为什么? you could have asked mrs zhang for advice高二英语you could have asked mrs zhang for advice,for she is an expert at it yes a whole dayA will be wasted B would be wasted C had been wasted D was wasted