根据对话内容，从对话后的选项中选出能填入空白处的最佳选项，选项中有两项多余选项。

--What seems to be the problem?

--    小题1:    

--How long have you been like this?

--Since Saturday night.

--____ 小题2:    

--Yes, I also feel lighthearted.

--Can you think of anything you ate Saturday that might have caused it?

--All I can think of is the fish I had. It didn’t taste quite right.

--____ 小题3:     Now I’ll give you some medicine. Take it and you should be feeling better soon.

--____ 小题4:     

--I also suggest that you follow a special diet.

--____ 小题5:     

--You should stick to eating lighter foods.

A．What’s that?

B．That might be it.

C．Thank you, doctor.

D．Any other problems?E. I have a running nose.

F. Have you seen a doctor?

G. I have a terrible stomachache.

废气分析是通过对焦炉中热煤气燃烧产生的废气中（）含量的测定，来计算燃烧的空气系数，从而达到对燃烧情况检查的目的。

A、CO₂

B、O2

C、CO₂

D、CO₂  O₂  CO