还请高手帮我看看 下面句子是什么结构的句子。。感激不尽

Question

I. Decide which type of sentence each of the following belongs to and then choose the corresponding letter.
1. It is a pleasure to read good books.（ ）
A. periodic sentence B. compound sentence
C. balanced sentence D. loose sentence
2. She missed the step and sprained her ankle.
A. periodic sentence B. compound sentence
C. simple sentence D. loose sentence
3. Mary had to give up watching TV, for she must take the exams.
A. complex sentence B. compound sentence
C. simple sentence D. compound-complex sentence
4. She decided to study English though she was interested in music.
A. periodic sentence B. compound sentence
C. balanced sentence D. loose sentence
5. There were the translators in their booths, and the girl secretaries at the doors, and the reporters grumbling and scribbling in their seats.
A. periodic sentence B. compound sentence
C. balanced sentence D. loose sentence

Answer 1

A,B,A,C,D
从语法结构的角度上，句子可分为简单句、并列句和主从复合句。从修辞角度上，句子可分为松散句(loose sentence)、圆周句(periodic sentence)和平衡句(balanced sentence):

(1) 松散句在英语句子中占很大比例。一般说来松散句适用于描写几个同等重要的观点和事实。松散句中没有跌宕起伏，全是平铺直叙，句子简单，意思直截了当，便于理解和使用。如：

I am very interested in physics when I was in high school, but I finally came to this university to study mathematics. (句子重点强调的是对物理感兴趣。)

Finally I came to this university to study economics, though I am very interested in computer science. (句子重点强调最后来大学学习数学这一事实。)

(2) 圆周句主要意思在后，不读到句末，就不可能了解句子的全部意思。圆周句中的高潮一般出现在句子的末尾，可以用这种句设置悬念，吸引读者。如果使用得好，可以收到一种特殊和效果。如：

Unless I get some money, I can’t go. (此句是圆周句，句子的中心意思是I can’t go, 原因在中心意思的前面，可以设置悬念。)

I Can’t go, unless I get some money. (此句则为松散句，看起来自然一些。)

(3) 平衡句是指结构相同而意思相反的句子的组合。平衡句属正式英语文体，常用在说明文或议论文中，对其中的观点加以比较或对比，从而使文章的中心思想更加鲜明突出，以加强读者的印象。如：

This is true but not new; that is new but not true.

In peace, children bury their parents; in war, parents bury their children.

You should eat to live, not live to eat.

The politician is concerned with successful elections whereas the statesman is interested in the future of the people.

Simple sentence是简单句，就是只有主谓宾的很简单的结构。Compound sentence是并列句，就是有多个并列的主谓结构的,而且这些结构是地位等同的，也就是没有从属关系，就像你举的例子。Complex sentence 是复合句，它有多套主谓结构，但是这些结构之间有从属关系，比如有主句和从句之分的。Compound-complex sentence是并列复合句，就是既有compound sentence,u又有complex sentence的句子。
另外，你的例子里面有逗号和没逗号的句子是一样的，因为都有两套平等的（没有从属关系）主谓结构，因而都是并列句（compound sentence）。正式写作时推荐用加逗号的。

Answer 2

A,B,A,C,D