I told him many times but he failed ( )(understand)it.

I told him many times but he failed ( )(understand)it. i told him many times but he failed _____（understand) it. I 've told him several times but he ____ doesn't understand i've told him several times but he____doesn't understand （）many times,but he still could not understand it. ____ many times but he still couldn't understand it he had been told many times but he still couldn't understand His mother has told him many times,but it did not help ___ many times but he still could not understand it.(tell) I wrote to him many times but he never ____( reply)用恰当形式填空 ______ many times,he still could not understand it. 1.（）many times,he couldn't understand it.