英语完形填空it was an unforgettable experience. we sat in a boat waiting for Ofai

原文如下
Unforgettable experience
It was an unforgettable experience,we sat in a boat waiting for Ofai.He was swimming under water.There were many beautiful shells at the bottom.If he could find some and bring them up,he would make a lot of money.It was a good and fast way to become rich.My uncle was with us to take care of us.Suddenly I saw Ofai wave his arms.Then I could see a large dark fish moving under the water.All at once I was frightened to hold my breath.
“A shark!” cried my uncle.An anxious expression suddenly appeared on his face.He was thinking of how to save Ofai.We stared at my uncle and waited for him to take actions.
The fish came near.Now we could see him better.He was of a yellow-brown color and as big as our boat.What could we do to help Ofai?He had been under water for more than a hour.So by now he must be very tired and it was difficult for him to swim fast enough to get out of the trouble.Thinking that Ofai’s life was in great danger,my uncle could stand it no longer.Without delay he took his knife and jumped into the water.Down he went after the man-eating fish.The shark was heading straight for Ofai.Then,suddenly,the fish turned.My uncle’s strong arm had sent the knife deep into the side of the great fish.The water turned red as blood ran from the shark.
Now Ofai had time to reach the top.At last he was safe in the boat.But the fish was angry.He turned to come at the man who had hurt him.As he swam to my uncle,he opened his great mouth.Again the knife went forward.This time it cut deep into the shark’s nose.
For a minute the shark lay still.Now Uncle Harry could swim to the top.Ofai quickly pulled him into the boat.It wasn’t long before the shark came to life.He hit the boat with such a hard blow that the sides were almost pushed in.We rowed as hard as possible and finally we were safe on the seashore.
It was my uncle’s courage and ability that saved Ofai and all of us.We learned a lesson from this experience that courage means everything in time of great danger.We will never forget this experience.