Yesterday we __ an expert to help solve this problem.A calle

Yesterday we __ an expert to help solve this problem.A calle Help me to solve this problem I wonder __ we can solve this hard problem.A.wh i wish i __(know)how to solve this problem. I can help you to solve this problem. any one can help me to solve this problem? help to solve the problem? we have got to ( )a new way to solve this problem This is a s_____ problem.We must solve it we found this problem difficult to solve solve为什么不用被动 can,we,learn,solve,a,to,forget,problem,by,it we can solve a problem by learning to forget