关于X线产生条件的叙述,错误的是() A.电子源 B.高速电子流 C.阻碍电子流的靶

题型:单项选择题 A1/A2型题

问题:

关于X线产生条件的叙述,错误的是()

A.电子源

B.高速电子流

C.阻碍电子流的靶面

D.高速电子与靶物质相互作用

E.X线管的靶面均由钼制成

考点:放射医学技术(士)医学影像设备医学影像设备题库
题型:单项选择题 A1/A2型题

Children’s literature traces its beginnings to preliterate times, when ancient storytellers passed tales and legends from generation to generation in the oral tradition. William Caxton, who established England’s first printing press, published books of etiquette, fables and legends. However, these didn’t constitute a body of work that could be considered literature for children. Because children at that time were considered "miniature adults", books were didactic in nature. The content for young readers consisted mainly of religious instruction, rules of behavior, ethical messages, and moral platitudes. In 1774, Englishman John Newberry changed children’s publishing when he began to create books with attractive formats, quality illustrations, and sturdy bindings, that were designed primarily for children to enjoy. The oldest, and most prestigious award given for children’s books published in America, is the Newberry Medal.
In the following century, children’s literature began to bloom. Hans Christian Andersen’s wonderful stories like "The Ugly Duckling", and "The Little Mermaid", and Grimm brothers collected two volumes of German folktales that included stories such as "Snow White" and "Rumpelstiltskin". Childhood came to be recognized as a joyful and carefree period of life, and books celebrating it began to be published. Charles Dodgson (Lewis Carrol) wrote the fantasy "Alice in Wonderland", the first book that was intended purely for children’s enjoyment without any pretense of instruction. Edwards Lear’s books of nonsense poetry delighted both young and old readers. In North America, books for a young audience were becoming popular as well. Kate Douglas Wiggin wrote "Rebecca of Sunnybrook Farm", Louisa May Alcott wrote "Little Women", and Samuel Clemens (Mark Twain) created Tom Sawyer and Huckleberry Finn. By the end of the century, the pious and moralistic books of earlier times had been replaced by writing designed to amuse and entertain a young audience. In the 1800s color printing was introduced, and by the middle of the 19th century, the rough illustrations that characterized earlier children’s books had been replaced by works of art that captured the word and some of the story.

The word "characterized" underlined in Paragraph 2 most probably means ______.

A.rejected

B.described

C.devalued

D.amused

题型:单项选择题 A1/A2型题

影响同年龄女性基础代谢的主要因素是

A.体表面积
B.身高
C.体重
D.胸围
E.体质指数

题型:单项选择题 A1/A2型题

水平尺中的两个水准管是呈()布置的。

A.平行

B.垂直

C.交角

D.随意

题型:单项选择题 A1/A2型题

一级化学防护服装为连式全密封结构。

题型:单项选择题 A1/A2型题

吸门

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