I worked as a waitress for a few months. I was not a great w

I worked as a waitress for a few months. I was not a great waitress and I worked in a restaurant that served mostly older people who, however, have not learned that ten percent of their expense is no longer a tip that waitresses can live on – let alone a college student working hard for 20 hours a week!
One night, when I was still working two hours after shift(轮班) was supposed to finish, all that I wanted was for my last table to clear out so I could clean and go home. My last customer caught me on her way out and asked if I had change for a twenty. I dug through my pocket and turned out my night’s earnings—a small amount of $14.
She smiled at me and said, “That is enough.”
My eyes were full of tears as I made the uneven(不等价的) exchange. “Thank you, ”I said in a low voice.
I heard her little boy ask why she did that and she explained that I’d had a hard night and she just wanted to help me out. I even heard her words, “Reach out your hands when somebody needs help.” I noticed the little boy nodded his head. Not only did her kindness touch my hurried and tiring life, but she also taught her son an important lesson that night.
I do not know her name, but I will always remember her.
1. According to the passage, at that time the author was ___________.
A. a full-time worker               B. still a college student
C. a school-leaver                 D. a secretary in a big company
2. Why did the woman want an uneven exchange?
A. She was to thank the author for her service.
B. She was in great need of change to buy a gift for her son
C. She was only to teacher her son a lesson.
D. She only wanted to give a hand to the author.
3. What was the woman’s son’s attitude to what she did at last?
A. Unbelievable.                  B. Acceptable.
C. Disappointed.                  D. Amazed.
4. What did the woman probably teach her son?
A. To live a hard life.
B. To give a waitress a more than 10% tip.
C. To show kindness to those  who need help.
D. To make an uneven change.