I don't think it's your（)错误.

A. be very grateful to sb for sth
B. It's all my fault.
C. be much obliged to sb for sth
D. be so thankful to sb for sth
E. I'd appreciate it if...
F. I'm terribly sorry.
G. I owe it to your help.

A. Don't mention it.
B. You are welcome.
C. welcome.
D. Not at all.
E. Forget it.
F. My pleasure.

A. Sorry, I didn't mean to hurt you.
B. I apologize for the terrible mistake.
C. I'm so sorry to you for...
D. It's my fault. I apologize for being so careless.
E. Please excuse me.

A. Never mind.
B. That's ok.
C. I don't think it's your fault.
D. Forget it.
E. Don't mention it.
F. It doesn't matter.