日常对话。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。选项中有两项为多余选项。
Acceptionist：Can I help you？
Daniel：Yes, I’m doing some research on Roman civilization. 
Acceptionist：These books over here are about ancient history. 
Daniel：Can I check this one out？
Acceptionist：    .It’s for reference only, so it must stay in the library.But you’re welcome to look through it.
Daniel：Ok. 
Acceptionist：All right.They’re due back next Wednesday.
Daniel

A．I’m sorry.

B．It doesn’t matter.

C．Thanks for your help.

D．They might be helpful.

E.They must be useful for you.
F.And I’d like to check these books out.
G.Do you have any books on the subject？