There is a student who really loves learning English. Day and night, he never miss a single chance to speak English.
One day, he bumped into a foreigner when he was walking on the road. He felt very sorry so he said:
"I am sorry."
"I am sorry too(two).", answered the foreigner.
"I am sorry three...", the student replied at once.
"What are you sorry for(four)?", the foreigner was surprised.
"I am sorry five."...
嗯，就是这样了。