简述用户用户地区特征的分类情况。

设X₁，X₂，…，X_n(n＞2)相互独立且都服从N(0，1)，Y_i=X_i=

(i=1，2，…，n)．求
1.D(Y_i)(i=1，2，…，n)；

2008年度“房地产开发企业施工房屋面积”最大的三个地区的面积之和比2007年度该三个地区之和增加了( )。

A．7615万平方米

B．7595万平方米

C．7535万平方米

D．7505万平方米

阅读表达（共5小题；每小题3分，满分15分）

阅读下面的短文，并根据短文后的要求答题。（请注意问题后的词数要求）

(1) The word addiction usually makes you think of alcohol or drugs, but in modern-day society we are seeing some new kinds of addictions. Some people are compulsive (难以自制的) shoppers. Others find it impossible to pull themselves away from their work. Still others spend countless hours watching TV or playing computer games.

(2) Over the years, shopping has become a very common activity. Many people enjoy going to stores more and more every day, but it’s more than a common hobby for some of them. They have turned into shopaholics. They are people who simply enjoy shopping and walking around spending money without being able to stop doing. They are booked on shopping and usually buy things that they don’t need. Even though they don’t have enough money, they buy everything they want.

(3) The question is, why do they have this addiction? There isn’t a specific answer. Some people go shopping when they are sad, worried, upset or lonely and they want to feel better. They use this activity as a way to forget their problems. Shopaholics say they feel more important and better after they buy something. They also tend to have this addition when they feel guilty.

(4) Shopaholism seems to be harmless addiction, but it can _____. Some of them can be psychological. If this is the case, people addicted to shopping should go to a support group to help them break this habit. However, the process, like for most addictions, is long, and they suffer a lot. It can also cause financial problems. They just think about satisfying their feelings, so they spend money they don’t have. They get deep in debt, and they can even go bankrupt and get sent to prison.

76. List three activities that might develop into addictions based on the test. (Please answer within 8 words)

①___________②___________③____________

77. What is the main ides of the Paragraph 3? (Please answer within 8 words)

_________________________________________________________________________.

78. Fill in the blank in Paragraph 4 with proper words. (Please answer within 6words)

____________________________________________________________________.

79. Which sentence in the text is the closest in meaning to the following one?

Accordingly, these shopaholics should turn to a certain organization for help so that they can stop compulsive shopping.

____________________________________________________________________.

80. Translate the underlined sentence in Paragraph 2 into Chinese.

______________________________________________________________________.

下列化合物中哪一个分子中不具有环戊烷多氢菲化学骨架（）。

A.睾丸酮

B.胆汁酸

C.前列腺素

D.皮质醇

E.胆固醇

竖井井口平台，应比地面至少高出（），井口应有严密的井盖，只有当吊笼罐升降时，才准许打开井盖。

A.1m

B.1.5m

C.0.5m

D.1.2m