选内容补全对话/短文

Lu Ban was a craftsman. One day a leaf  (cut / cuts) his finger. He looked at the leaf  (careful / carefully). There were many  (tooth / teeth) on the leaf and they were sharp. So he made a tool with teeth like  (these / this). It could cut things. It was a saw. It was the first saw in the world. People are still  (use/ using) this tool today.