Then he spoke slowly, but I could not understand him

Then he spoke slowly, but I could not understand him but I （could） not understand him He spoke slowly but clearly so that we could follow with him He spoke so fast that ______of us could understand him. The speaker spoke so slowly that we could understand him ___ He spoke so fast that we could hardly understand him.把这句子改下, He spoke very clearly.All of us could understand him.合并为一句 he could not understand what she found wrong with him. But ,I could not find her/him . ___ ,but he still could not understand it （）many times,but he still could not understand it. ____ but he still could not understand it.