问题 问答题 简答题

立柱活柱筒基本结构特点是什么?

答案

参考答案:

1.对材料强度、延伸率可焊性等要求与缸筒相通。

2.大部分是由合金无缝钢管与柱头、活塞等焊接加工而成,个别小直径立柱的活柱采用圆钢加工而成。

3.活柱外表面必须耐磨、耐腐蚀,要求与导向套的配合精度一般为H9/f9(D4/dc4),表面粗糙度为

4.表面要有防腐耐磨镀层。常用的为双层镀鉻,后镀硬鉻。可用铜打底,镀硬鉻或镀铜等。

填空题
阅读理解

There is a popular belief among parents that schools are no longer interested in spelling. No school I have taught in has ignored spelling or considered it unimportant as a basic skill. There are, however, vastly different ideas about how to teach it, or how much priority(优先) it must be given over general language development and writing ability. The problem is, how to encourage a child to express himself freely and confidently in writing without holding him back with the complexities of spelling.

If spelling becomes the only focal point of his teacher’s interest, clearly a bright child will be likely to “play safe”. He will tend to write only words within his spelling range, choosing to avoid adventurous language. That’s why teachers often encourage the early use of dictionaries and pay attention to content rather than technical ability.

I was once shocked to read on the bottom of a sensitive piece of writing about personal experience: “This work is terrible! There are far too many spelling errors and your writing is illegible(难以辨认)”. It may have been a sharp criticism of the pupil’s technical abilities in writing, but it was also a sad reflection on the teacher who had omitted to read the essay, which contained some beautiful expressions of the child’s deep feelings. The teacher was not wrong to draw attention to the errors, but if his priorities had centred on the child’s ideas, an expression of his disappointment with the presentation would have given the pupil more motivation to seek improvement.

46.What is the problem with students’ writing?

How to write freely.

What to write.

How to write freely with right spelling.

How to write freely with his own words.

47.Why do teachers encourage early use of dictionaries?

Students will express themselves confidently.

Teachers will not worry about so many spelling errors.

Students’ writing will be good both in content and in technical ability.

Teachers will be proud of their clever students.

48.The author seems to think that ______.

spelling is unimportant in school.

teachers have the same view about teaching spelling.

teachers should pay much attention to the student’s technical ability.

the student’s idea is the most important in his writing.

49.In paragraph 3, the attitude of the author is ________.

A.suspicious

B.indifferent

C.subjective

D.objective50.The main idea of the passage is _______.

the importance of students’ writing

the importance of teachers’ attitudes

how to deal with the spelling errors

how to deal with technical ability and content