问题 问答题 简答题

为了提高沉淀池的分离效果,人们常采取什么措施?

答案

参考答案:

①从原水水质方面着手,改变水中悬浮物的状态,使其易于与水发生分离。

②从沉淀池结构方面着手,创造宜于颗粒沉淀分离的边界条件。

选择题
阅读理解

阅读理解。

     Time spent in a bookstore can be most enjoyable, whether you are a book-lover or merely you

are there to buy as a present. You may even have entered the shop just to find a shelter from a sudden

shower. Whatever the reason, you can soon become totally unaware of your surroundings. The desire

to pick up a book with an attractive "dust-jacket" is irresistible(不可抗拒的), although this method of

selection ought not to be followed, as you might end up with a rather dull book. You soon become

engrossed in some book or other, and usually it is only much later that you realize you have spend far

too much time there and must dash off to keep some forgotten appointment- without buying a book,

of course.

      This opportunity to escape the realities of everyday life is, I think, the main attraction of a book-shop. There are not many places where it is possible to do this. A music shop is very much like a bookshop.

You can wander around such places to your heart's content. If it is a good shop, no assistant will

approach you with inevitable greetings "Can I help you, sir?" You needn't buy anything you don't want.

In a bookshop an assistant should remain in the background until you have finished browsing(浏览).

Then, and only then, are his services necessary. Of course you may want to find out where a particular

section is, but when he has led you there, the assistant should retire carefully and look as if he is not

interested in selling a single bok. You have to be careful not to be attracted by the variety of books in

a bookshop. It is very easy to enter the shop looking for a book on ancient coins and to come out

carrying a copy of the latest best-selling novel and perhaps a book about brass-rubbing-something

that had only slightly interested you up until then. This sort of thing can be very dangerous. Apart from

running up a huge account, you can waste a great deal of time wandering from section to section.

1. What does the underlined part "dust-jacket" in the first paragraph probably mean?

A. The title of a book.

B. A kind of clothes.

C. Book cover full of dust.

D. Protecting paper cover of a book.

2. In the author's opinion, what is the main attraction of a bookshop?

A. You can spend much time in the bookshop.

B. It has many books with attractive dust-jackets.

C. It enables you to forget the realities of everyday life.

D. You don't have to go for unpleasant appointments.

3. According to the passage, what will happen in a good bookshop?

A. Nobody will take notice of you.

B. You will feel as if you were in a music shop.

C. You will find yourself undisturbed and satisfied with your browsing.

D. The assistant will greet and treat you in a very friendly way.

4. Picking up books that slightly interest you can be dangerous because ________.

A. you may forget about the book you plan to buy

B. it costs you too much money and time

C. it makes you break your appointment

D. you have to give up the best-selling book