为什么不能无限提高硫化温度？

使用磺胺类药物时，病人出现紫癜是（）

A.肾脏毒性反应

B.对血液系统的毒性

C.对肝脏的毒性

D.二重感染

E.过敏反应

下面哪些一般不是监视管理访问的原因？（）

A.绝对不能信任管理员

B.监视可以缓解与滥用特权关联的风险

C.监视可以确定是否创建了未经授权的管理账户

D.监视可以提供对管理活动的监督

There (1) not one type of reading but several according to your reasons for reading. To read carefully, you have to (2) your reading speed and technique (3) your aim (4) reading. Skimming is a technique necessary for quick and efficient reading.

When skimming, you (5) the reading (6) quickly in order to get the (7) of it, to know how it is organized, (8) an idea of the tone or the intention of the writer. Skimming is (9) an activity which (10) an overall view of the text and (11) a definite reading competence.

Skimming doesn’t need reading all the material, but it doesn’t mean that it is an (12) skill for the lazy, because it need a high degree of alertness and concentration.

When you read, you usually start with (13) understanding and move towards detailed understanding rather than working the other way round. But (14) is also used after you have already carefully studied and you need to (15) the major ideas and concepts.

In order to be able to skim quickly and (16) through a text, you should know where to look for what you want. In preview skimming you read the introductory information, the headings and subheadings, and the summary, if one is provided. (17) this skimming, decide whether to read the material more thoroughly, and select the appropriate speed (18) you read.

The same procedure (19) for preview skimming could also be used to get an overview. Another method would be to read only key words. This is done by omitting the unnecessary words, phrases, and sentences.

In order to skim efficiently and fulfill your purpose, (20) practice is necessary.

15().

A.reverse

B.review

C.revise

D.revert

影响氧化还原反应速度的主要因素有反应物的浓度、酸度、温度和催化剂。( )