根据句子意思，用所给单词的适当形式填空。未提供单词的根据上下文填入适当的词。

    Long ago, there was a big cat in the house. He was strong he caught many mice while they were stealing food, all the mice were afraid of it. One day the mice had a meeting to talk about the way to deal with their common enemy. They didn't agree with each other. Some said this, some said that.

    At last a young mouse got up said that he had a good idea, "We could tie a bell around the neck of the cat. when he comes near, we can hear the sound of the bell run away."

    Everyone approved of this proposal (建议), an old wise mouse got up and said, "That is all very well, who will tie the bell to the cat?" The mice looked at each other, nobody spoke. Until now, they haven't decided whether it is a good idea not.