影响汽车行驶平顺性的主要因素有哪些？

阅读理解。

     My name is Jack. When my family moved to America from a small village in Guangdong, China, we

brought not only our luggage, but also our village rules, customs and culture. One of the rules is that young

people should always respect the elders. Unluckily, this rule led to my very first embarrassment in the United

States.

     I had a part-time job as a waiter in a Chinese restaurant. One time, when I was serving food to a middle-aged couple, the wife asked me how the food could be served so quickly. I told her that I had made sure they got

their food quickly because I always respect the elderly. As soon as I said that, her face showed great

displeasure. My manager, who happened to hear what I said, took me aside and gave me a long lecture about

how sensitive(敏感) Americans are and how they dislike the description"old". I then walked back to the table

and apologized to the wife. After the couple heard my reason, they understood that the problem was caused by

cultural differences, so they laughed and were' no longer angry.

     In my village in China, people are proud of being old. Not so many people live to be seventy or eighty, and

people who reach such an age have the most knowledge and experience. Young people always respect older

people because they know they can learn from their rich experience.

     However, in the United States, people think"growing old" is a problem since "old" shows that a person is

going to retire or that the body is not working well. Here many people try to keep themselves away from

growing old by doing exercises or jogging, and women put on make-up, hoping to look younger. When I told

the couple in the restaurant that I respect the elderly, they got angry because this caused them to feel they had

failed to stay  young. I had told them something they didn't want to hear.

     After that, I changed the way I had been with older people. It is not that I don't respect them any more; I

still respect them, but now I don't show my feelings through words.

1. Jack brought the couple their food very fast because _____.

A. the manager asked him to do so

B. he respected the elderly

C. the couple wanted him to do so

D. he wanted more pay

2. In Jack's hometown, _____.

A. people dislike being called "old"

B. people are proud of being old

C. many people reach the age of seventy or eighty

D. the elderly are the first to get food in restaurants

3. After this experience, Jack _____.

A. lost his job in the restaurant

B. made friends with the couple

C. no longer respected the elderly

D. changed his way with older people

4. Which of the following is TRUE?

A. The more Jack explained, the angrier the couple got.

B. Jack wanted to show his feelings through words after his experience.

C. The manager went back to the table and apologized to the couple.

D. From this experience, Jack learned more about American culture.

5. Which is the best title for this passage?

A. Different countries, different customs.

B. Old people, old customs.

C. Different restaurants, different services.

D. Differences between old and young.

硒元素（Se）是一种非金属元素，含适量硒元素的矿泉水有益人体健康．在硒酸（H₂SeO₄）中Se的化合价是（　　）

A．+6

B．+4

C．+3

D．+2

I haven’t heard_____ her for a long time since the last letter but I did hear _____her through my friend.  

A．from; about

B．of; from

C．about; of

D．from; from

某煤矿是增值税一般纳税人，2009年8月发生下列业务：
(1)开采原煤6000吨，将其中4000吨直接销售，取得销售额400000元(不含增值税)；将其中1000吨连续加工成居民用蜂窝煤销售，取得销售收入200000元(含增值税)；
(2)采煤过程中开采天然气500000立方米全部销售，价税合并收入金额150000元；
(3)销售使用过3年的旧机器一台，价税合并收取16000元；
(4)当期购买采煤机械吸取的增值税专用发票上注明税金17000元，外购材料发生进项税9860元，该批材料用于生产加工煤炭制品；
(5)购买材料发生运费500元，销售居民用煤炭支付运费1500元，取得运输部门开具的普通发票。
假定上述需要认证的票据均经过了认证，该矿山资源税税率4元/吨，邻县天然气税率15元/千立方米。该企业上期增值税留抵税额1200元，根据以上资料回答下列问题：
(1)该企业应纳的资源税；
(2)该企业可抵扣的增值税进项税；
(3)该企业销售原煤的增值税销项税；
(4)该企业销售蜂窝煤的增值税销项税；
(5>该企业销售天然气的增值税销项税；
(6)该企业当期应纳增值税。

按聚合机理不同可以将形成聚合物的反应分为（）

A、连锁聚合反应和逐步聚合反应

B、离子聚合和缩聚反应

C、配位聚合反应和离子聚合反应

D、缩聚反应和加聚反应