Lesson seventeenth

I'm' is a contraction for the words 'I am.' The phrase 'working on' relays a physical or mental effort towards an accomplishment.

Here are some examples:

"I'm working on a big project."
"I'm working on training my dog."
"I'm working on making new friends."
"I'm working on educating myself."
"I'm working on my homework."
"I am working on painting a house."
"I am working on a new idea."
"I am working on my computer."
"I'm working on my website."

Saying you are 'sorry to' expresses a feeling of sympathy or regret.

Here are some examples:

"I'm sorry to be so late."
"I'm sorry to hear about your sick mother."
"I'm sorry to waste your time."
"I'm sorry to make you feel so sad."
"I'm sorry to frighten you."
"I'm sorry to disagree with your decision."
"I'm sorry to call so late."
"I'm sorry to admit what I did."
"I'm sorry to end this relationship."
  Source:http://www.manythings.org/elllo/