在下列数据中，最接近生活实际的是[ ] A. 一支新2B铅笔的质量约是400 g

人口计生工作探索建立的长效工作机制是什么？

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

双母线接线方式的可靠性比单母线接线方式高，但设备投资较大。

现要挂号邮寄120本书，每11本重2千克，邮局规定(为计算方便，略有改动)：印刷品的邮费是每千克0.8元，不足1千克的以1千克计，每件限重5千克，挂号费每件0.6元(含手续费0.3元)，试问：这批书最省的邮费为多少元( )

A．20.6

B．20

C．19.6

D．19.2

一家三口人，三年前三人年龄之和是70，且当时妈妈的年龄是儿子的5倍，妈妈的年龄比爸爸小4岁，爸爸今年多少岁（）

A．36

B．34

C．40

D．37