液压缸常用的密封方法有()密封和()密封。

题型:填空题

问题:

液压缸常用的密封方法有()密封和()密封。

考点:钳工技能考试机修钳工考试机修钳工考试题库
题型:填空题

工厂有一批长3dm、宽2dm的矩形铁片,为了利用这批材料,在每一块上裁下一个最大的圆铁片⊙O1之后(如图所示),再在剩余铁片上裁下一个充分大的圆铁片⊙O2

小题1:(1)求⊙O1、⊙O2的半径r1、r2的长;

小题2:(2)能否在剩余的铁片上再裁出一个与⊙O2同样大小的圆铁片?为什么?

题型:填空题

小儿结核病的化学治疗原则是

A.早期治疗

B.联合用药

C.用大剂量

D.规律用药

E.坚持全程

题型:填空题

用于确诊急性白血病的检查是()

A.细胞遗传学检查

B.细胞化学染色

C.免疫学检查

D.骨髓象

E.血象

题型:填空题

某一静态RAM芯片的存储容量为64K×1b,其地址总结有()条。

A.64

B.32

C.16

D.8

题型:填空题

American Museum of Natural History is one of the largest natural and historic museums in the world and one of the main natural history research and education centres in the United States, set up in 1869 and located in the west of the Central Park, Manhattan District, New York. It (1) 7 hectares in its total area, (2) classical types of buildings. The (3) of ancient creatures and humanity is (4) the first place of all the museums in the world, (5) the representative samples from South America, Africa, Europe, Asia and Australia were collected, besides those from the (6) country, the United States.In the museum, there are five kinds of exhibits, including astronomy, mineralogy, human history, and animals in the (7) times and those in modern times. There are thirty-eight exhibition halls with different (8) from 500 to 1,500 square metres. Besides these, there is a Roosevelt Memorial Hall in (9) of President Roosevelt who supported the (10) of the museum, which is also used to have a special exhibition, showing the new important (11) on natural sciences and (12) affairs and social problems, and special topics connected closely with the life of the citizens. Besides this, it is also used for avocation (13) to have all kinds of scientific activities in the laboratories, centres of natural science and centres for citizens. There are more than 10 (14) research departments mainly(15) for collection of samples, research and work of publication.In the museum, there are (16) and sub-libraries of Aulspond ancient amniote, with about 300 thousand books and magazines (17) natural history, many of(18) are very valuable monographs for the first edition. It has published many expert books and magazines, and a large number of propaganda materials, (19) which are the two magazines, Natural History and Members of Museum that have the biggest (20) of their magazines.

19()

A.in

B.by

C.for

D.among

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