阅读下列短文, 从下面每小题的A、B、C、D四个选项中选出最佳选项, 并在答题卡上将相应字母编号涂黑。
Every morning, a woman baked bread for her and her family and an extra piece for a hungry passer-by. She would always put the extra piece of bread on the window sill.
She noticed that a hunchback(驼背)came every day and took the extra piece. Instead of saying thanks to her, he would say, “The bad you do remains with you. The good you do comes back to you!"
This went on, day after day. Finally, the woman got very angry. ”He is so impolite!” she said to herself.
One day, she added some poison to the piece of bread she prepared for him! When she was about to put the piece of bread on the window sill, she stopped. “What am I doing?” she said. Immediately, she threw the bread into the fire, prepared another one and put it on the window sill.
As usual, the hunchback came, picked up the bread and said those words to her.
That evening, there was a knock on the door. It was the woman's son, hungry and weak.
Looking at his mother he said, “Mom, I was too hungry to walk any further a mile away. But just then, an old hunchback was kind enough to give me a piece of bread.”
Then the woman realized the meaning of the words, “The bad you do remains with you. The good you do comes back to you!”
)，会对人体产生一定
危害。该原子中中子数和质子数之差是