
Once on a sunny day, a boy and his dad went to the lake to swim. The boy was so excited! As they approached the lake, they noticed a big engine. The engine made a lot of noise and spewed smelly smoke. The boy started to cry and asked his father why he had to bring his big noisy engine to the lake.
The father said, "It was selfish of me to bring this engine. I'm sorry it bothers you so much. Now, let's go have some fun swimming!".
But the boy was still scared. He didn't want to swim with the big noisy engine near the lake. The father said, "Let the engine bother us for a bit and I'll take it away soon. Just come and swim with me, ok?".
But the boy refused. After some time, it became too unbearable and the father had to take his engine away. The boy was so happy! He jumped in the lake and started to swim with his dad.
But his happiness soon ran out as they noticed that the engine had left something very bad behind in the lake. The water was murky and filled with rubbish.
The father said, "It was so selfish of me to bring the engine here. We won't be able to swim here anymore". 
The boy sadly said, "Yeah, it's all gone".
