I worked on the problem ____ a long time and I worked it out

I worked on the problem ____ a long time and I worked it out I worked on the problem for a long time and I worked it out I worked out the problem so( )(easy) I don't understand the way_____they worked out the problem. The problem is difficult,____,he has worked it out.A:though the problem is very difficult,but he worked it out ____ a la I don`t understand the way ___they worked out the problem A. 英语翻译Well,I worked in business for a long time and so I under The problem is too hard.I haven't ( )the answer A.WORKED ON I have worked out the plan and I must put it into pratice 帮我 i still remember the time ____ _____ we worked on the farm You worked for a long time.____ ____ ____ ____ you worked!(改