七、阅读短文，回答问题
A frog lived at the bottom (底部) of a well.
Every day, it sang in the water, “Ah, I live in this well. It is the perfect place in the world. I jump around every day. Life is so happy!”
One day, a big sea turtle travelling on land passed by the well. It heard the singing of the frog. And it asked, “Hi, have you ever seen the sea?”
The frog shook its head and said, “No. I have never seen the sea. Is it as big as my well?” Then it added, “How about coming down into my well and having a visit?”
The sea turtle nodded (点头) and tried to climb into the well. But the well was too small for it to get in. Then he gave up and said, “Sorry, my friend. I can’t get in because your well is too small. I just want to tell you there is a place called ‘sea’. It is deep and wide (宽的), and seems to have no ends! When I swim in the sea, I feel so happy and free! I think you should come and have a look!”
Then the sea turtle waved goodbye and continued his journey. The poor little frog simply sat there, with its mouth wide open. At that time, he started to realize how small his well was.
1. What did the frog think of living at the bottom the well at first?

2. How did the frog imagine the sea when he first heard of it?

3. What did the sea turtle tell the frog about after he gave up getting into the well?

4. Why did the frog sat with its mouth wide open at last?

5. What can you learn from the story?