They were able to take a great many photographs of the mountains.在这句话中,为什么要加a?

it was thirty years until they were able to reunite 能代替 it was thirty years before they were吗 were able to have done they will be able ,as it were,to see and hear us in action.in Some of these singers were able to sing English songs just as well as native speakersMeaning Wo xiang zhi dao ta shen me yi si Only in that way( )find out how this kind of animal lived and then finished the research on time.A. could they B. they could C. were they able to D. they were able to They weren't able to come because they were so busy at two hours ago .这句话有没有问题 Only in that way _____ find out how this kind of animal lived and then finished the research on timA.could theyB.they couldC.were they able to D.they were able to 选哪个?为什么? were you able to keep them?翻译 In the end they were able to climb the top of the mountain.上面这句话怎么意思? They were able to take a great many photographs of the mountains.在这句话中,为什么要加a? They were able to get to the village in the end.（句意不变）They ____ ____ get to the village in the end. 英语句子改错:They hardly were able to finish the difficult job on time.只有”hardly were”这部分要改.. they have (able)to speak english well They didn't want to come with us at first,but then we ()presuade them.A.would B.couldC.were able to D.had to ------ we think it is a miracle that they were able to do soA to this day B up till now 选哪个?新概念上面的迷糊了 Everyone ( ) run away from the burning building A can B is able C was able to D were able to 英语翻译But the people of London were also in the front lines,and they did not have the satisfaction of being able to fight back. It took me a long time before I was able to fully appreciate what they __ for me.A.had doneB.didC.would doD.were doing寻详解