he didn't work out the problem ( ) I explained ( ) to him

一道英语单选题,I didn't manage to work out the problem( )the teache 英语翻译I didn't quite follow him because he explained the theor 英语翻译1.i explained the problem to him,but he did not believe 19.The students didn’t manage to work out the problem ______ The students didn’t manage to work out the problem ______ th （急!）：It isn't easy for him to work out this problem.I though 1.单词拼写：I an able to work out the problem,but he is ____(不能）t 2.I took him an hour to work out the problem .( 同义句 ) I find that it it hard for him to work out the problem.句型转换 改为同义句I find that it is hard for him to work out the problem. Without your help,I can't work out the problem He has been a 连词成句 work,belive,don't,out,problem,he,the,can.I