圆柱被平面所截,其截交线为平行两直线,则截平面与圆柱轴线()。A、垂直 B、平行 C

题型:单项选择题

问题:

圆柱被平面所截,其截交线为平行两直线,则截平面与圆柱轴线()。

A、垂直

B、平行

C、倾斜

D、随意

考点:冷作钣金工铆工(高级)铆工(高级)题库
题型:单项选择题

尽量随机地选择人群可以控制的偏倚是

A.选择偏倚
B.信息偏倚
C.混杂偏倚
D.报告偏倚
E.失访偏倚

题型:单项选择题

南北半球的分界线是______,东西半球的分界线是______和______。我国位于______和_____。

题型:单项选择题

脑栓塞的栓子来源最常见于()

A.心源性

B.动脉粥样硬化性斑块

C.脂肪栓子

D.空气栓子

E.癌细胞栓子

题型:单项选择题

阅读理解。

     Chrysanthemums (菊花) are to the fall what tulips are to the spring.

     In ancient China, chrysanthemums (or 'mums' for short) were first planted thousands of

years ago. People chose the chrysanthemum as their Flower for October, a symbol of the rest and ease

that followed the season's final harvest. Then they symbolized a scholar in retirement (隐居) and were

one of the four noble plants, along with bamboo, the plum flower, and orchid.

     The Japanese hold the chrysanthemum as a symbol of the sun. They consider the orderly unfolding of

its petals to be a symbol of perfection. They also think that a single chrysanthemum petal placed in the

bottom of a wine glass encourages a long and healthy life. The Japanese even have a National

Chrysanthemum Day on September 9, known as the Festival of Happiness.

      In the United States during colonial times, its popularity grew such that mums now reign as "Queen of

the Fall Flowers." Mums remain the most widely grown pot plant in the country and the largest

commercially produced flowers. Chrysanthemums generally represent cheerfulness and rest. So they are

welcomed throughout the British Isles and North America for any occasion, such as football games and

parties. In other countries such as Italy, Belgium and Austria, however, their association with the dead

makes chrysanthemums acceptable only for funerals and graves.

1. Why did people in ancient China choose the chrysanthemum as their Flower for October,

    a symbol of ________?

A. having a month of celebration.  

B. having relaxation after one year's of hard work.

C. loving this kind of flowers during this month.

D. having another good harvest the next year.

2. The Japanese consider the chrysanthemum as a symbol of the sun because________.

A. people like the flower just as they like the sun

B. the flower with its nice petals represents a symbol of perfection

C. people find the flower having no perfect petals when it is unfolding

D. the flower unfold its petals orderly just like the sun  

3. Mums are loved not only in the Unite States but in the British Isles  as they stand for ________.  

A. cheerfulness and rest    

B. happiness and joy

C. wealth and health        

D. luck and chance

4. In some European countries people use chrysanthemums to express  their feeling of _______.  

A. regret     

B. cold    

C. sorrow  

D. approval

题型:单项选择题

沙门菌食物中毒的食品主要为蛋类和家禽肉,是因为

A.病禽宰后污染室温下细菌繁殖

B.家禽因经泄殖腔带染,室温下细菌繁殖

C.病畜宰后污染,室温下细菌繁殖

D.健康禽蛋不带染而在加工中污染,室温下细菌繁殖

E.以上都不对

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