Grammatical Question - pls

Still, I have a question about the lines extracted from the flick "Elizabeth." Elizabeth says, "My people are my only concern. Yes, my only concern is my people." Is there any grammar usage that can define this sentence? I know they two mean the same thing. What I really don't get is : in... show more Still, I have a question about the lines extracted from the flick "Elizabeth."

Elizabeth says,
"My people are my only concern.
Yes, my only concern is my people."

Is there any grammar usage that can define this sentence? I know they two mean the same thing. What I really don't get is : in the first sentence, the object does not match with the plural be-V. I know concern is a singular abstract N, but can anyone tell me what kind of grammar it is categorized?

Or it is just because people use it in the colloguial way?
I need to know it in grammar type. And pls give examples.
It's better to be more detailed.
Update: Btw, if you are interested in western culture, maybe you can go check my another question:
http://tw.knowledge.yahoo.com/question/?qid=1305100508985
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