短文填空。根据下列短文内容，根据首字母提示，在短文后的空格处填上一个恰当的词，使短文通顺，每空一词，含缩略词。
Do you know the differences between the new building and the old ones?
Old buildings h 1 brick(砖)and stone walls. The walls hold up the b 2 .
In cities, many modern building 1 3 as if they are made just of windows.Walls of dark glass reach
high into the air. Many buildings are m 4 than 50 stories(层)tall.
Are walls of glass strong e 5 to hold up the new buildings? No, The new glass walls do not hold up
the buildings,b 6 they only cover up the frame(框架)made of steel. Have you ever watched a new
building going up? The steel frame is built f 7 . Then the glass walls are hung on the frame. When the
building is f 8 , the frame does not show. The outside looks like windows without walls. The glass walls
shine i 9 the sun with no decoration(装饰).Many people find t 10 beautiful just as they are.
