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【单选题】
Lunar sight-seeing trips and orbiting space hotels are within reach, moon walking astronaut Edwin'Buzz' Aldrin said last week, but some who favor space tourism worried about its 'giggle factor'. Astronomers have known for years that a source of intense energy emissions lies at the center of the Milky Way Galaxy, obscured from view by vast clouds of dust and gas. In February, 1992, researchers at the Max Planck Institute in Garching, Germany, reported evidence that the mysterious energy source is a gigantic black hole. Observations have shown that many strong energy sources lie at the heart of the Milky Way. One of them, called Sagittarius A, is thought to be the actual center of the Galaxy, the point about which the great spiral of stars rotates. Sagittarius A is a powerful emitter of radio waves and X-rays. Astronomers have considered two possible explanations for the identity of Sagittarius A. They theorized that it is either a compact duster of normal stars or a super-massive black hole containing as much as a million or more suns. The German scientists reported that they found strong evidence in support of the black hole explanation. The astronomers used a new telescope high in the Andes Mountains of Chile to obtain the sharpest images ever made of the region around Sagittarius A. The image shows that Sagittarius A is a single, small object rather than a duster of stars. The researchers also found that a bubble of gas is expanding outward from Sagittarius A. This expanding gas is similar in temperate, density, and composition to the jets of gas that astronomers have observed flow hag away from the centers of many other galaxies. Such jets are thought to be generated by accretion disks surrounding enormous black holes. Accretion disks are vast, swirling masses of gas and dust that give off titanic amounts of energy as they are sucked into the black hole. The similarity between the jets emitted by some galaxies and the gas bubble surrounding Sagittarius A supports the idea that Sagittarius A is a super-massive black hole. According to the German researchers, the energy source at the center of the Milky Way Galaxy ______.
A.
has been covered up by vast clouds of dust and gas
B.
still remains unknown to astronomers
C.
has proved to be a black hole
D.
actually provides power for the rotation of file great spiral of stars
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【单选题】下列哪个不是网站建设的系统设计方法()
A.
自顶而下
B.
自底而下
C.
自左向右
D.
不断增补
【单选题】. 甲企业(增值税一般纳税人) 2016年11月销售一批自产高档化妆品,不含增值税销售额为120万元,已知该批高档化妆品成本为70万元,成本利润率为5%,高档化妆品的消费税税率为15%,则甲企业当月增值税销项税额的下列计算中,正确的是( ) 。
A.
120万×17%=20.4万元
B.
70×(1+5%)×17%=12.5万元
C.
70×(1+5%)÷(1-5%)×17%=14.7万元
D.
120×(1+5%)÷(1-5%)×17%=25.2万元
【单选题】下面句中指定词语属于形容词作名词的一项是()。
A.
民恶灭绝,我生育之,生育
B.
水则载舟,水则覆舟,覆
C.
贼仁者,谓之贼;贼义者,谓之残,贼
D.
举笃敬,兴孝弟。笃敬
【简答题】计算题目中 ZJ9的工程量
【单选题】甲企业为增值税一般纳税人,2016年12月购进一批生产免税产品和应税产品的原材料,取得增值税专用发票,注明价款为100万元,增值税税额为17万元。当月免税产品的销售额为100万元,应税产品的不含税销售额为200万元。已知增值税税率为17%,则甲企业当月可以抵扣的进项税额为( )万元。
A.
5.67
B.
8.5
C.
11.33
D.
17
【单选题】在齿轮加工中作为齿轮轮齿分度的圆称为
A.
分度圆
B.
齿根圆
C.
齿顶圆
【简答题】要求有一张集体一起讨论的照片上传 2、 以小组为单位,提交一份演讲心得,并指出小组在演讲前后的工作是否到位, 有哪些不足与可取之处! 3、报告内容最好明确成员的角色任务分配,每一个角色所承担的任务是什么?
【单选题】在齿轮加工中作为齿轮轮齿分度的圆称为?
A.
分度圆
B.
齿根圆
C.
节圆
D.
齿顶圆
【简答题】计算题目中ZJ9的工程量,断面图如图所示。
【单选题】在齿轮加工中作为齿轮轮齿分度的圆称为
A.
节圆
B.
分度圆
C.
齿根圆
D.
齿顶圆
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