为了安装方便，圆柱齿轮的传动比一般在（）范围。

[单选题]Passage1One of the world's first videogames，Tetris，has turned thirty years old，and its brand is anything but old school.But what's kept people swiping and clicking to ensure each row of blocks stays aligned and disappears into the virtual world since its development in 1984 Soviet Russia？A combination of new platforms and an attracting psychological appeal.Maya Rogers, the CEO of Blue Planet Software, the sole agent of the Tetris brand, said the protection of the game's core over the last three decades has aided its longevity. As mobile and social become two of the largest sources for gaming these days, Tetris isn't showing any signs of losing its appeal. Currently appearing on over 50 different gaming platforms, from the 1983Nintendo Entertainment System(NES) to smartphones, Tetris is sold on over 425 milion mobile devices. More than 20 billion games of Tetris Battle have been played on Facebook, too. There's something psychologically entrancing about the game, that's kept people hooked through the years."Play a game of Tetris," said Rogers," and satisfy your craving to create order out of chaos."Plus, there's the added quality of playing Tetris and never feeling wholly fulfilled."There's no correct move that you can make,"said Neubauer, a loyal player of the game who work as a senior analyst at Saibus Research, an independent research and advisory firm," The quest for the perfect move never ends."Tom Stafford,a professor of cognitive development and psychology at Sheffield University in the U.K, says that Tetris has been around so long because it transports gamers into a different realm when they play."It's a world of perpetually generating uncompleted tasks, "he said. As he's said in the past, too, "Tetris is the granddaddy of puzzle games like Candy Crush saga-the things that keep us puzzling away for hours, days and weeks.""Tetris is pure game: there is no benefit to it, nothing to learn, no social or physical consequence,"he added."It is almost completely pointless, but keeps us coming back for more."Since it was developed, Tetris has been ________.

[单选题]挖掘社区志愿力量，共同参与社区矫正工作属于（　）。

[多选题]根据地方政府使用资金权限大小可将政府间转移支付分为（）。

[单选题]石油中（）对有色金属具有很高的反应性，由它所造成的金属腐蚀现象是人们非常关注的问题。

[单选题]行政沟通内容非常复杂，按沟通层次可分为上层、中层和基层信息i个层次，下列属于上层信息的是：

[单选题]下列体表定位标记的叙述，错误的是（　　）。

[单选题]利用斜楔固定钢丝绳绳端（）方便。

[单选题]药物通过消耗能量的、逆浓度梯度的转运，其转运机制是（）

[单选题]指出下列正常分娩机制哪项是正确的？（　　）

[单选题]农业有着艺术永远无法比拟的实践性。湖北农民在节庆的巫文化中，按照自己的需要造就了各种神灵，向它们许愿，祈求它们保佑农业生产的顺利进行。这种节庆活动，意外地促成了农业生产经验的发展，比如“春社”中放在社神前的“社种”，竟使农民能利用温室观察稻种出芽的情况；“嫁毛娘”的过程中，燃烧的火把消灭了大量飞蛾。 对这段文字理解最准确的是（）。

[单选题]为了安装方便，圆柱齿轮的传动比一般在（）范围。

[单选题]斜齿圆柱齿轮传动比直齿圆柱齿轮传动重合度（）。

[问答题]已知一正常齿制的标准直齿圆柱齿轮，齿数z1=20，模数m=2mm，拟将该齿轮作某外啮合传动的主动齿轮，现须配一从动齿轮，要求传动比i=3.5，试计算从动齿轮的几...

[问答题]已知一正常齿制的标准直齿圆柱齿轮，齿数z 1=20，模数m=2mm，拟将该齿轮作某外啮合传动的主动齿轮，现须配一从动齿轮，要求传动比i=3.5，试计算从动齿轮的...

[问答题]一对外啮合标准直齿圆柱齿轮，已知模数m=2mm，齿数z 1=25，z 2=75。求齿距p，全齿高h，分度圆直径d 1，d 2，齿顶圆直径d a1，齿根圆直径d ...

[单选题]一对外啮合的标准直齿圆柱齿轮，中心距a=160mm，齿轮的齿距p=12.56mm，传动比i=3，则两齿轮的齿数和为（）。

[单选题]一对外啮合的标准直齿圆柱齿轮，中心距a=160mm，齿距p=12.56mm，传动比i=3，则两轮的齿数和是（）。

[问答题]一对外啮合标准直齿圆柱齿轮，已知模数m=2mm，齿数z1=25，z2=75。求齿距p，全齿高h，分度圆直径d1，d2，齿顶圆直径da1，齿根圆直径df2，标准中...

[判断题]渐开线标准直齿圆柱齿轮传动，由于安装不准确，可能产生中心距误差，但其传动比的大小仍保持不变。

[判断题]渐开线标准直齿圆柱齿轮传动，由于安装不准确，产生了中心距误差，但其传动比的大小仍保持不变。