问题 单项选择题 A1型题

关于肿瘤发病机制,下列错误的是()

A.从遗传角度来说,肿瘤是一种基因病

B.瘤细胞的多克隆性扩增形成肿瘤

C.原癌基因的激活或肿瘤抑制基因的失活导致细胞的恶性转化

D.肿瘤的发生是一个长期的、分阶段的、多种基因突变积累的过程

E.肿瘤的发生是免疫监视功能丧失的结果

答案

参考答案:B

解析:引起遗传物质DNA损害的各种环境与遗传的致癌因子可能以协同或者序贯的方式,使细胞发生转化。被转化的细胞可先呈多克隆性增生,经过一个漫长的多阶段的演进过程,其中一个克隆可相对无限制地扩增(单克隆性),通过附加突变,选择性地形成具有不同特点的亚克隆,从而获得浸润和转移的能力,形成恶性肿瘤。

阅读理解

阅读理解

     Ask savvy investors(投资者) how they learned their first lessons about money, and they'll probably

tell you lessons their parents taught them.

     The money values we learn as children stay with us the rest of our lives. If you are a parent, teaching

your children the value of saving and investing will benefit them the rest of their lives. Here's what you can

do:

     Help your child begin to save. Open savings accounts for your children, and teach them how the bank

adds interest to their savings that makes their money grow. Encourage your children to save a little from

every bit of money they receive, such as allowances, birthday gifts, etc. You may even want to set up a

matching program, contributing fifty cents for each dollar your child saves.

     Teach your child about stocks(股票). A child in elementary school can start learning about how

businesses work. Once your child understands the basics, ask him or her to think about some of the

businesses that might be good stock investments. Then use Morningstar Mutual Fund Guide(available

at your library)to find a quality mutual fund that holds some of these companies, or a mutual fund that

caters to children such as the Stein Roe Young Investor Fund. Many funds accept regular monthly

investments as low as $50 a month, so these funds can be a good way to teach children about the stock

market while saving for their college education.

     Encourage early IRA(个人退休金账户)saving. The new Roth IRA is a great way for children who

are working in summers or after school to begin saving for their future. Imagine how much money you'd

have today if you had saved $3,000 a year since you were a teenager!

      Let your kids handle their own money. We all learn by doing, so letting your kids manage a segment

of their budget(预算)will let them earn valuable financial lessons.They may make mistakes, but they will

be small mistakes that may help them avoid larger mistakes as adults.

1. Which would be the best title for this passage?

A. Why to Teach Your Children to Save

B. How to Teach Your Children to Save

C. Tips for Saving for Children

D. Start Good Saving Habits Early

2. A matching program means ________.

A. that you should set a good example to your children

B. that you should provide enough money for children so that they can save some

C. that you encourage your children to compete with each other in saving

D. that you encourage your children by giving some extra money for them to save

3. According to the author, you should teach your children about investment when he/she is ________.

A. in the kindergarten  

B. in primary school

C. in middle school  

D. in college

4. Which of the following is NOT an advantage of the Stein Roe Young Investor Fund?

A. It is usually with high benefits.

B. It accepts regular monthly investments.

C. It accepts small investments as low as $50 a month.

D. It caters to children who can afford small investments.

5. The advantage of letting your kids manage their budget lies in ________.

A. that they will make great businessmen in the future

B. that they will know the difficulty of managing a budget

C. that they will avoid making bigger mistakes in the future

D. that they will share happiness of managing their own budget

单项选择题