The problem is difficult,____,he has worked it out.A:though

The problem is difficult,____,he has worked it out.A:though The problem is difficult,（ ）he has worked it out. the problem is very difficult,but he worked it out ____ a la The problem is difficult ,but he worked it out____. The maths problem is very difficult,.I work it out,though 为什 I worked on the problem ____ a long time and I worked it out he has worked out the problem.的被动形式 The difficult math problem he has just put out is ___me. ____,he can not work out the difficult problem is it difficult ______(finish) ____(work) out the problem in The problem is very difficult.He can't work it out.(合并为一句） the math problem is so difficult that he can'twork it out (改