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【单选题】

C The idea of being able to walk on water has long interested humans greatly. Sadly, biological facts pr us ever accomplishing such a thing without artificial aid --- we simply weigh too much, and all our mass pushes down through our relatively small feet, resulting in a lot of pressure that makes us sink. However, several types of animals can walk on water. One of the most interesting is the common basilisk Basilicus basilicus, a lizard(蜥蜴)native to Central and South America. It can run across water for a distance of several meters, avoiding getting wet by rapidly hitting the water’s suce with its feet. The lizard will take as many as 20 steps per second to keep moving forward. For humans to do this, we’ll need huge feet that we could bring up to our ears in order to create adequate “hitting.” But fortunately there is an alternative: cornflour. By adding enough of this common thickening agent to water (and it does take a lot), you can create a “non-Newtonian” liquid that doesn’t behave like normal water. Now if the suce of the water is hit hard enough, particles(粒子)in the water group together for a moment to make the suce hard. Move quickly enough and put enough force into each step, and you really can walk across the suce of an adequately thick liquid of cornflour. Fun though all this may sound, it’s still rather messy and better read about in theory than carried out in practice. If you must do it, then keep the water wings handy in case you start to sink --- and take a shower afterward! Walking on water hasn’t become a reality mainly because humans __________ .

A.
are not interested in it
B.
have biological limitations
C.
have not invented proper tools
D.
are afraid to make an attempt
题目标签:粒子
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【单选题】关于Sprites粒子的描述错误的是()

A.
Sprites粒子在赋予纹理贴图前显示为小正方形
B.
无论摄像机的摆放角度怎样变化,总是面朝摄像机
C.
Sprites粒子不能调入外部贴图
D.
如果纹理图片有Alpha通道,则Sprites粒子就使用图像的透明属性

【单选题】近代粒子物理学研究表明,物质构成的最小单元是( )。

A.
分子和原子
B.
原子核和中子
C.
原子核和亚原子
D.
夸克和轻子

【简答题】当特征福射通过试样燕气时,被下列哪种粒子吸收: A.激发态原子A. 离子

B.
基态原子
C.
分子
D.
:C
E.
r>4、在原子分光光度计中,最广泛采用的光源是:
F.
空心阴极灯
G.
无极放电灯
H.
氢灯
I.
钨灯

【单选题】Gravity is a slippery beast. We don’t know how strong it is, how it works or how fast its effects move. But this year we made progress. October saw the most accurate measurement yet of Newton’s gravit...

A.
two things far apart might vibrate in unison
B.
the ripples in space-time are only imagined
C.
there exist gravitational waves
D.
abrupt, violent cosmic events lead to gravitational waves