A、He did research in Kahn’s factories. B、He read a lot of background materials. C、He focused on Kahn’s classical design. D、He we

W: Didn’t you write a paper about Albert Kahn last semester?
M: Yes, for my history of architecture class.
W: Oh, I am taking it now and [12]I have to do some research on industrial architecture. I need to read up on Kahn’s factories. So I would like to see what you wrote about them,
M: I don’t think my paper will help; I focus on his classical design like Clements library and office buildings, but you are interested in the modern building he is famous for.
W: Yes, he is best known for his factory, especially the auto plants in Detroit. He made a breakthrough in industrial design. [13]You know before his time, factories were so narrow and inefficient, but his factory provided enough light and air and open space. So the cars could be assembled in one huge plant.
M: I remember reading that previously, factories had wooden frames and the heavy machinery made the buildings vibrate and there were fire hazards too. But when Kahn started to design auto plants around the turn of the century, reinforced concrete had just been invented. [14]With the reinforced concrete, not only were the buildings solid and fireproof but they were cheap to put up too!  
W: You seem to know a lot of about his industrial career.  
M: Actually even though I wrote about his other works, [15]I did a lot of background reading. Let me see if I can dig up that paper for you. There were some books of articles included in my biography that you might want to look up at the library.  
W: Thank you. It will be a great help for me.
12.Why does the woman want to read the man’ paper about Albert Kahn?
13.What do we know about Kahn’s factories according to the conversation?
14.What changes did the reinforced concrete bring to the architecture industry?
15.Why does the man know so much about Kahn’s industrial career?