It provides background information on the topic.
and It gives the main topic of the paper.
Efficient means someone who is working in a well-organized way and plans things well. So think of what a character would do being "well-organized" "well-planned" ...etc.
The phrase during separate semesters helps reveal the meaning of the word concurrent which means at the same time.
Answer:
I knew then I had to have a house. A real house. One I could point to. But this isn’t it. The house on Mango Street isn’t it. For the time being, Mama says. Temporary, says Papa. But I know how those things go.
