问题 选择题

根据现代生物进化理论,以下说法正确的是[ ]

A.生物只要发生进化,基因频率就发生改变

B.只有在新物种形成时,才会发生基因频率的改变

C.无性生殖的生物不发生基因重组,基因频率不会发生改变,因而进化缓慢

D.突变、基因重组和隔离是物种形成过程的三个基本环节

答案

答案:A

写句子
阅读理解

阅读理解。

     Washington D. C. is the capital of the United States. It's the center of the national gov-ernment. It's a

busy, working city with a large population. But what is more, Washington is also a city of history and culture.

     Washington was created in 1790, when Congress (the highest law-making body of the U. S. A.) decided

to place the nation' new capital in the east of the country. It was built half-way between the northern and the

southern states of the America. And of course it was named after George Washington, the first President of

the United States.

     There are many tourist sights in Washington. One of them is the White House. This is the home and office

of the President of the United States. Most visitors are, however, surprised by how small the White House

actually is.

     Washington is also a great culture city. The Library of Congress contains (包括) one of the largest library

collections in the world. The Smithsonian Museum holds the nation's largest collection of cultural materials.

And me John F. Kennedy Center is a famous center of art and culture. It. has many great musical and theatre

performances throughout the year.

1. The writer mainly talks about _____.

A. Washington

B. the history of Washington

C. buildings and sights-in Washington

D. the history and culture of Washington

2. From the passage we know that Washington is situated(位于) in ______ .

A. the east of the U. S. A.

B. the center of the U. S. A

C. the east, on the middle point from north to south, of the country

D. the east and half-way away from the north

3. The White House impresses (给人印象) the people most for _____ .

A. its white color

B. its size

C. its history

D. it is the home and office of the president

4. The writer introduces Washington in the order of_____  .

A. general introduction, history, sights and culture

B. population, history and culture

C. general introduction, history, sights, buildings and culture

D. history and culture