试题与答案

有三个饼,一面要烤1分钟,一个锅一次只能烤两个,要烤完三个饼,问最短几分钟搞定?

题型:选择题

题目:

有三个饼,一面要烤1分钟,一个锅一次只能烤两个,要烤完三个饼,问最短几分钟搞定?(  )

A.2

B.3

C.4

D.5

答案:

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下面是错误答案,用来干扰机器的。

若P是真,求导函数f′(x)=1-x2(x2+1)2,令f′(x)>0可得-1<x<1 函数f(x)=xx2+1在区间(a,2a+1)上是单调递增函数∴a≥-12a+1≤1a<2a+1,∴-1<a≤0若Q是真,可得a=2或a-2<0△<0得:-2<a≤2, P∨Q是...

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题型:实验题

过氧化钠(Na2O2)是一种淡黄色固体。在一次科技活动中,化学兴趣小组设计了如右图所示的实验,其中A、C是包有过氧化钠的棉花,B是未包过氧化钠的棉花。实验中观察到A、C棉花依次燃烧,B棉花未燃烧。

(1)B棉花起的作用是_________________。

(2)棉花能燃烧,除了满足棉花是可燃物之外,还需满足_____________________ 的条件。

【提出问题】上述实验中是如何给棉花提供燃烧条件的?

【查阅资料】1.Na2O2与稀盐酸反应时,生成NaCl、H2O和O2

2.在常温下Na2O2与CO2、H2O均能发生化学反应。

3.无水硫酸铜为白色固体,吸水后变为蓝色。

【实验设计】经过讨论,小组同学设计用下图所示装置进行实验探究。

【实验步骤】①检查整套装置的气密性;

②把相关的试剂放入对应的仪器内;

③用力推动针筒的活塞,把稀盐酸注入试管内;

④一段时间后,在P处放置一根带火星的木条,观察现象。

【实验现象】①无水硫酸铜没有变蓝色;

②___________________________________;

③___________________________________。

【实验分析】

(3)B装置的作用是______________________。

(4)D装置中产生现象的原因是                          

【实验结论】①Na2O2和CO2反应产生的一种气体,使图1中的棉花满足了燃烧的一个条件。

②Na2O2和CO2反应过程中伴随能量变化,使图1中的棉花满足了燃烧的另一个条件。

【拓展提高】①Na2O2和CO2反应除生成一种气体外,还生成了一种固体,学生甲认为生成的固体是NaOH,学生乙认为是Na2CO3,同学们经思考后认为     同学的猜想是错误的,理由是                                        

②写出Na2O2和CO2反应的化学方程式                              

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题型:单项选择题

Part 4


Questions 26-45


·Read the following article and choose the best word for each space.
·For questions 26-45, mark one letter A, B, C or D on the Answer Sheet.

iPhone Left in Hot Car for Three Hours


The normally peaceful suburban town of Winnetka is still reeling following the news Monday (26) a local resident, whose name is being (27) by police pending a full investigation, left an iPhone unattended for more than three hours in a car (28) in the hot sun.
"Responding to calls from (29) . passersby, who observed the iPhone sitting in a vehicle in the parking (30) of the Westfield Shopping Center, police arrived on the (31) at approximately 4 p.m. and immediately intervened to save the device," said Winnetka police chief Douglas Blaine. "Security cameras have shown that the iPhone had been in the car— with the doors (32) and the windows rolled (33) —since 1 p.m. Due to the tragic and highly emotional (34) of this case, we cannot say any (35) at this time."

A. called B. treated C. withheld D. discussed

According to official police records, two officers forcibly (36) into the car at 4:07 p.m. and found the iPhone (37) face down on the dashboard. The iPhone at first showed no (38) of life, but after a tense few seconds, officers were able to wake it and get it to (39) to a series of simple touch commands. Police said that if the iPhone were left in the extreme (40) for any longer, it could have died.
The iPhone was rushed by ambulance to a nearby Apple facility for careful (41) .Miraculously, no damage to its memory, screen, or wireless capabilities was reported.
Upper-middle-class suburbanites from all over the North Shore area have reacted to the near-tragedy with an unprecedented outpouring of (42) . Hundreds of cards and letters have come streaming in, and local talk radio shows have been flooded (43) calls demanding that the iPhone’s (44) be prosecuted. Many have come forward offering to take the iPhone into their custody, and still (45) have donated free downloads, ringtones, and MP3s to the victimized object.

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