Read the following text to answer the question.

    Two frogs had lived in a village all their lives. They thought they would like to go and see the big city that was about ten miles away.

    They talked about it for a long time and at last they set off to the city.

    It was a hot day, and they soon began to feel tired. They had only gone a little way when one said to the other, "we ,ust be nearly there, can you see the city?" "No," said the other frog, "but if I climb on your back I might be able to see it."

    So he climbed up on the back of other frog to see the city.

    Now when the frog put up his head, his eyes could only see what was behind. And now what was in the front. So he saw the village they had just left. "Can you see the city?" asked the frog who was below. "Yes," anwered the frog who had clombed up, "I can see it. It looks just like our village."

    Then the frogs thought it was not worthwhile going any further. They went back and told the frogs in the village that they had seen the city, and it was just like theirs.

"... at last they set off to see the city." (Paragraph 2)

The underlined word means ...