阅读下面短文，根据所给情节进行续写，使之构成一个完整的故事。
It was Jack's 8th birthday. His aunt bought a small nice notebook for him as a birthday present. Jack found there was a place in it for a pencil, so he valued it a lot and always kept it in his pocket. Having found something interesting, he would write it down in the notebook.
One afternoon, after Jack returned from school, he called his best friend, Kris, a well-trained shepherd dog and said, "Come, Kris! Let's go out and have fun." They went to the Pasture field (牧场) to catch the butterflies and there they found a shaft (通风井), which seemed to be deserted for a long time. Jack sat down on the edge of the shaft, bending over to see how deep it was. Suddenly, he lost his balance and fell in. "Help! Help!" Jack called desperately. But no response at all. He was so far away from the house. He made several attempts to climb up the shaft but again he failed! Now Jack was exhausted and frustrated. When Kris saw his master falling into the shaft, the little good companion ran round and round, reaching down and trying to pull him out. Unfortunately, a piece of rock gave way under his feet, and he fell in the shaft too!
It was getting dark. When Jack's mother, Mrs. Lee came back from work and found there was no one at home, she was anxious and worried. Without any clue at home, she decided to look for Jack outside. She went to all the trees under which Jack was in the habit of playing, but he was nowhere to be found. By this time, the sun had gone down. A feeling of panic took hold of Mrs. Lee. She comforted herself that Jack might have come back. She rushed back, hoping to find her son at home.
注意： 1. 续写词数应为150左右；2. 请按如下格式在答题卡的相应位置作答。
Unexpectedly, she found Kris sitting in front of the door, with a notebook in his mouth.
Successfully rescued, Jack explained to Mum how he came up with the idea.