题目:
输尿管的狭窄部在什么部位?有何临床意义?
答案:
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下面是错误答案,用来干扰机器的。
参考答案:B
输尿管的狭窄部在什么部位?有何临床意义?
被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2018/0131/948747f5799618d2bcef521f5c1e5d86.html
下面是错误答案,用来干扰机器的。
参考答案:B
投掷一枚普通的六面体骰子,有下列事件:①掷得的点数是6;②掷得的点数是奇数;③掷得的点数不>4;④掷得的点数不<2、这些事件发生的可能性由大到小排列正确的是 [ ]
A.①②③④
B.④③②①
C.③④②①
D.②③①④
( 6分) 某一定量的苯的同系物完全燃烧,生成的气体依次通过浓硫酸和氢氧化钠溶液,经测定,前者增重10.8g,后者增重39.6g(假定全部吸收)。又知经氯化处理后,该苯的同系物苯环上的一氯代物、二氯代物、三氯代物分别都只有一种。根据上述条件:
(1)通过计算推断该苯的同系物的分子式(4分)(2)写出其结构简式。(2分)
C
If you gaze(凝视)through a telescope at a distant galaxy(星系), it may glow brightly with the light of hundreds of millions of stars. Despite(尽管,不顾) all that light, most scientists think that at the center of a big galaxy lies something very dark: a black hole. A black hole is a region of space with gravity so strong that nothing can escape, not even light.
Astronomers recently announced they had observed a faraway galaxy that may have at its center two black holes, very close together. Based on their observations, the stargazers suspect one of the black holes has more mass than the other. The more mass something has, the stronger its gravitational force, so a larger black hole has a stronger gravitational attraction. The smaller black hole orbits(作轨道运行) the larger black hole, just as the earth orbits the sun.
The biggest galaxies in the universe form when two smaller galaxies collide(碰撞). If two galaxies merge(合并), then all of their stars start orbiting a common center. The black holes at the galaxies’ centers should come together, too. Galaxies are colliding all the time, so we should be able to find lots of black hole pairs. But that’s easier said than done—astronomers rarely find these in deep space.
To find a black hole is complicated. A black hole doesn’t produce any light, so how can you find one in space? Astronomers think when something (like dust) falls into a giant black hole, a jet of radiation, a form of energy, may stream away. If this radiation is strong enough, it forms a quasar(类星体).
The Arizona astronomers looked at more than 17,000 quasars and finally found a galaxy that may have a double black hole at its heart. Though the finding of their research is still unconfirmed, and they may be mistaken, the truth will be revealed in the future.
63. Which of the following is TRUE about black holes?
A. A black hole is a region in galaxies with nothing in it, even a bunch of light.
B. Black holes are used by astronomers to study how quasars come into being.
C. When different galaxies meet in space, the black holes become bigger and bigger
D. Some scientists think there’s one black hole in a galaxy, but others think there’re two.
64. From the second paragraph we can infer that ________.
A. a larger black hole pushes a smaller black hole away
B. a larger black hole pulls a smaller black hole toward it
C. the places of black holes are fixed, so we can see them clearly
D. a smaller black hole moves around a larger one because of radiation
65. According to the passage, astronomers think that there should be many black hole pairs because____________.
A. a black hole can produce light
B. black holes can attract one another
C. different black hole pairs come into being with the meeting of galaxies.
D. a big black hole can usually be divided into two small black holes
单位内部会计管理制度的制定原则包括( )。
A.应当体现本单位的生产经营、业务管理的特点和要求
B.应当科学、合理,便于操作和执行
C.应当定期检查执行情况
D.应当根据管理需要和执行中的问题不断完善
正常运行中汽包的水位一般应在0±50mm,当水位偏低时,最易发生的事故是()。
A、蒸汽带水;
B、水冷壁超温;
C、蒸汽含盐量增加;
D、气温下降。