碎屑物质被胶结物胶结以后所形成的结构称为（）。A.碎屑结构 B.斑状结构 C.沉积结

以下关于数据的逻辑结构的叙述中，_______是不正确的。

A．数据的逻辑结构是数据间关系的描述

B．数据的逻辑结构不仅反映数据间的逻辑关系，而且反映其在计算机中的存储方式

C．数据的逻辑结构分为线性结构和非线性结构

D．树形结构是典型的非线性结构

肝脏密度异常包括()

A．肝内胆管积气 

B．肝实质积气 

C．门静脉积气 

D．肝弥漫性密度增高 

E．肝内局限钙化

阅读理解。

     Most people want to know how things are made. They honestly admit, however, that they hardly know

a thing when it comes to understanding how a piece of music is made. Where a composer (作曲家) begins,

how he manages to keep going-in fact, how and when he learns his trade-all are covered in complete darkness.

The composer, in short, is a man of mystery (神秘).

     One of the first things the common man wants to know about is the part inspiration (灵感) plays in a

composer's work. He finds it difficult to believe that composers are not much interested in that question.

Writing music is as natural for the composer as eating or sleeping for all. Music is something that the composer

happens to have been born for.

     The composer, therefore, does not say to himself:"Do I feel inspired?" He says to himself:"Do I feel like

working today?" And if he feels like working, he does. It is more or less like saying to himself:"Do I feel sleepy?"

If you feel sleepy, you go to sleep. If you don't feel sleepy, you stay up. If the composer doesn't feel like

working, he doesn't work. It's as simple as that.

1. What would be the best title for the text?

A. Composer: a man of mystery

B. Practice makes good music

C. Relation between sleeping and music

D. Music: product of nature

2. The words "covered in complete darkness" underlined in Paragraph 1 most probably mean _____.

A. difficult to be made

B. without any light

C. black in color

D. not known

3. Most people seem to think that a composer _____.

A. finds it difficult to write music

B. considers it important to have a good rest

C. should like to talk about inspiration

D. never asks himself very simple questions

4. The author will most probably agree that composers _____.

A. are born with a gift for music

B. are people full of mystery

C. work late at night for their music

D. know a lot about eating and sleeping

微分方程

的通解是______．

在三相对称正弦交流电路中，线电流的大小是相电流大小的（）倍。

A、1；

B、1.414；

C、1.732；

D、1.732或1。