According to the passage, what is one disadvantage of skyscrapers that have mirrored walls?

• A、 The exterior surrounding air is heated
  
  

• B、The building materials are very expensive.
  
  

• C、Construction time is increased.
  
  

• D、Extra air-conditioning equipment is needed. 
  
  

六、完形補文：第 41~50 題，每題 1.5 分，共 15 分。

下面的短文有 10 處空白，每處空白后的括號內有一個詞，請根據短文內容將其正確的形式填入文中，以恢復文章原貌。

I always enjoy the drive into Marley. It is a good straight road with ___41____(please) views of the countryside on either side. There are woods and hills, ___42____(village) and farms and, about halfway, a large lake. And because there is rarely much traffic on the road, I can ___43____(usual) enjoy the view as I drive along.

I was rather ___44____(annoy) the other morning, therefore, when a small green car began to drive very close behind me. I went a little ___45____(fast), hoping to get rid of it. But whenever I slowed down, the little car caught up with me. The driver, a middle-aged man, was grinning and ___46____(wave) to me. However, I did not know him.

"Perhaps I am doing something wrong," I thought. I ___47____(check) my lights and my indicator, but they were both in order. And I ___48____(certain) had not got a puncture. I did not slow down until I got to Marley. As I was ___49____(cross) the railway bridge into Marley, the lights turned red: I was waiting there when the little green car pulled up beside me. The driver got out and ___50____(tap) on my window. I opened it. "Can I help you?"I asked rather coldly. "I'm trying to help you!"the man said. "You see, your number plate fell off about fifteen miles back. I tried to attract your attention, but you didn't take any notice! "

The main purpose of the passage is to

• A、discuss the advantages and disadvantages of skyscrapers
  
  

• B、compare skyscrapers with other modern structures
  
  

• C、 describe skyscrapers and their effects on the environment
  
  

• D、 illustrate various architectural designs of skyscrapers