once he explained a maths problem to me u____ i understood i

once he explained a maths problem to me u____ i understood i i did not understood the problem until he had explained it这句 i did not understood the problem until he had explained it. 英语翻译1.i explained the problem to him,but he did not believe he didn't give me what i wanted ,but__he explained to me why i did not realize my mistake until he explained it to me改成倒装 I don't quite know the reason _______ he explained to me i found______difficult to work out the Maths problem. A:it i He let me repeat his instruction___sure that I understood wh i did not understand the problem until he had explained it.我 请问一个英语问题：I did not understand the problem.He explained it 两句 35.He __ to help me with my maths,but I refused his help ,as