问题 问答题 简答题

对于釜式反应器而言,搅拌装置必不可少,通常情况下,不同搅拌体系要求选择不同的搅拌器,请举例说明。

答案

参考答案:

例如:对于低粘度体系而言,一般采用浆叶尺寸较小、搅拌转速较高的浆式(平浆、斜浆)、透平浆和推进式搅拌器;对于高粘度体系而言,一般采用浆叶尺寸较大(螺杆式搅拌器除外),搅拌转速较低的锚式、框式、螺带式和螺杆式搅拌器,其中,采用螺杆式搅拌器时,一般与螺带式搅拌器或导流筒配合使用;对于粘度极高的体系,还可采用带刮板的螺带式搅拌器等,或采用双层或多层搅拌浆叶,或根据需要采用两种及其以上浆型组合。

阅读理解

  Language is always changing. In a society where life continues year after year with few changes, the language does not change, either. The earliest known languages had difficult grammar but a small, limited vocabulary. Over the century, the grammar changed, and the vocabulary grew. For example, the English and Spanish people who came to America during the sixteenth century gave names to all new plants and animals they found. In this way, hundreds of new words were introduced into English and Spanish vocabularies. Today life is changing very fast, and language is changing fast too.

 There are several major language families in the world. Some scientists say there are nine main families, but other scientists divide them differently. The languages in each family are connected, and scientists think that they came from the same parent language About 3 percent of the people in the world speak languages that are not in these major families.

60. The early language had ______.

A. a lot of problems                                      B. words and easy grammar

C. words but no grammar                                    D. grammar but not many words

61. In the next few hundred years we can expect language to ______.

A. stay exactly the same                             B. change a great deal

C. change only a little                                  D. add more words and drop some grammar

62. What this article shows is that ______.

A. languages change fast             B. languages really don’t want to change

C. language changes with changes of society     D. Spanish and English change

63. From this article we can see that ______.

A. language can change very slowly or very quickly

B. if we don’t change, then our language won’t change, either

C. we should give our plants new names

D. English and Spanish are the only languages that have changes

单项选择题