下列各项中，加横线的词语使用不恰当的一项是（    ）

A: Hello, Jim! What are you doing now?

B: Oh, I'm reading my report card.

A: I suppose you have passed all the exams. You are always hard-working.

B: It's true that I always do my homework by myself. But I often get nervous when I see the envelope from school.

A: How about your math this time? I know you don't do well in it.

B: It was lucky that I passed the math exam this time. We had a new math teacher this semester. She is a university graduate and works as a volunteer in our school. Her teaching has a good influence on my study and starts to open my eyes to the outside world.

A: That's really great. Does she like living in our hometown where the air is thin?

B: She said she felt happy with her decision.

A: By the way, I got a message for you. Your mother asks you to look after yourself well.

B: OK. Thank you.