计算:(-3x2n+2yn)3÷[(-x3y)2]n

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问题:

计算:(-3x2n+2yn3÷[(-x3y)2]n

考点:有理数除法有理数的乘方
题型:解答题

下列哪项是对内环境稳态实质的描述 [ ]

A.是神经和体液共同调节下实现的

B.温度、pH等理化性质呈现动态平衡

C.是各个器官、系统协调活动的结果

D.是体内细胞生活不可缺少的条件

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填空。

1.描写寄家书时的思想活动和行为,表达了客居他乡之人对家乡亲人深切思念的一首诗是________,作者是________。

2.《长相思》的作者是____代词人________,词中“_________________”一句 * * 旅途中将士的思乡之意自然流淌出来。

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Throughout the 19th century and into the 20th, citizens of the United States maintained a bias against big cities. Most lived on farms and in small towns and believed cities to be centres of (1) , crime, poverty and moral (2) Their distrust was caused, (3) , by a national ideology that (4) farming the greatest occupation and rural living (5) to urban living. This attitude (6) even as the number of urban dwellers increased and cities became an essential (7) of the national landscape. Gradually, economic reality overcame ideology. Thousands (8) the precarious (不稳定的) life on the farm for more secure and better paying jobs in the city. But when these people (9) from the countryside, they carried their fears and suspicions with them. These new urbanities, already convinced that cities were (10) with great problems, eagerly (11) the progressive reforms that promised to bring order out of the (12) of the city.

One of many reforms came (13) the area of public utilities. Water and sewerage systems were usually operated by (14) governments, but the gas and electric networks were privately owned. Reformers feared that the privately owned utility companies would (15) exorbitant (过渡的) rates for these essential services and (16) them only to people who could afford them. Some city and state governments responded by (17) the utility companies, but a number of cities began to supply these services themselves. (18) of these reforms argued that public ownership and regulation would (19) widespread access to these utilities and guarantee a (20) price.

(11)()

A.embraced

B.adopted

C.hugged

D.contained

题型:解答题

下列试剂中,()属混凝剂。

A、聚丙烯酰胺

B、硫酸亚铁

C、活化硅胶

D、海藻酸钠

题型:解答题

轴瓦()不好,间隙过大或过小,也可造成机泵轴瓦向外窜油。

A.润滑

B.紧固

C.调整

D.接触

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