如下图所示四个电路中,电阻R的阻值和电源电压已知,根据已知条件和电表的示数能测出

题型:选择题

问题:

如下图所示四个电路中,电阻R的阻值和电源电压已知,根据已知条件和电表的示数能测出电阻Rx阻值的电路是(   )

A.

B.
C.
D.
考点:其他方法测电阻
题型:选择题

听长辈说制作生伴菜不能添加黄瓜,难道黄瓜能使蔬菜中的营养素流失吗?

[查阅资料]

青椒等蔬菜中含有大量的维生素C,且维生素C能使蓝色的淀粉碘溶液褪色.

[实验操作]

步骤一:淀粉碘溶液配制:取1克淀粉,加入100毫升水,搅拌均匀,再加入1毫升碘酒溶液;

步骤二:分别榨取新鲜黄瓜汁与青椒汁.各取20毫升青椒汁分别倒入A、B两锥形瓶中,再分别加入黄瓜汁、蒸馏水各40毫升混匀,放置60分钟,中间每隔10分钟搅拌一次;

步骤三:取等量蓝色淀粉碘溶液分别装入两个烧杯,分别倒入A、B两溶液,搅拌均匀,静置观察.

[现象记录]

实验操作实验现象
淀粉碘溶液+青椒和黄瓜混合汁蓝色不消褪
淀粉碘溶液+青椒汁和蒸馏水蓝色褪去
根据上述过程回答下列问题:

(1)科学实验需要控制变量.下列情况会影响测定结果的是   

A.混合液放置时间不同       B.被测混合液的体积不同        C.锥形瓶的大小不同

(2)在步骤二中每隔10分钟搅拌一次,其目的是      

(3)能证实黄瓜汁把维生素C分解了的实验现象是       

(4)请指出该实验存在的缺陷:        

题型:选择题

完形填空(共20小题;每小题1.5分,满分30分)

阅读下面短文,掌握其大意,然后从16~35各题所给的A、B、C、D四个选项中,选出最佳选项。

Roberta appeared on the stage.She took a deep breath and began to   16  .Now she was Portia,a strong-willed   17   in Shakespeare’s The Merchant of Venice.The theater was filled with people.She was speaking with a power she had never before experienced,the words flowing

   18   from her.

  19 .Roberta had never acted in her life before the audition(选拔试演).She  20   being in front of other people.She was very   21   at school.She had never thought she was good enough at anything to  22  much attention.She stayed mostly to herself,making  23  friends.She had excellent grades,   24   she always thought that something was missing.

Two weeks before the audition,Roberta’s mother had heard about it and   25   her to join in.

“I can’t think of anyone else better suited to   26   the part.Remember all the plays you used to act out for us?”

Roberta looked down.“I’m not interested.”

Her mother wouldn’t let the   27   drop.“You’re just a little scared(害怕).Everyone gets scared.You know you   28  do it.The trick is to look past the   29   to find the love of what you’re doing.”

So Roberta had made an appointment(预约)with the head of the Drama Club.She had read the play and found herself excited by the  30 of speaking such rich words.In secret she practiced Portia’s part,  31  the lines by repeating them over and over.It wasn’t hard;she  32   every minute of it.Every time she spoke the words,she had a new  33   of the lines,as if Shakespeare had written Portia on many levels.

On the day of the audition,she   34   two of Portia’s famous speeches for the auditors.When she had finished,the head of the Drama Club announced the   35   was hers.

16.A.sing                            B.dance                     C.speak                        D.report

17.A.member                B.actress                       C.player                       D.character

18.A.weakly                 B.rapidly                      C.smoothly                   D.slowly

19.A.At first                 B.In fact                       C.After all                    D.In all

20.A.hated                    B.enjoyed                     C.appreciated               D.regretted

21.A.honest                  B.shy                           C.polite                        D.patient

22.A.avoid                   B.focus                        C.pay                           D.attract

23.A.few                      B.a few                        C.several                      D.many

24.A.or                        B.so                             C.for                            D.but

25.A.forced                  B.requested                   C.encouraged                D.reminded

26.A.accept                  B.play                         C.offer                         D.learn

27.A.role                      B.matter                       C.interest                      D.grade

28.A.can                      B.must                         C.may                          D.should

29.A.anger                   B.pain                          C.sadness                      D.fear

30.A.purpose                B.way                          C.idea                          D.importance

31.A.memorizing                                             B.organizing

C.checking                                                      D.improving

32.A.disliked                B.loved                        C.expected                    D.bore

33.A.consideration                                           B.description

C.selection                                                       D.understanding

34.A.practiced                     B.planned                     C.performed                 D.delivered

35.A.part                      B.play                          C.speech                       D.position

题型:选择题

新生儿淋菌结膜炎多在出生后多长时间内发病()

A.1~2周内

B.24小时内

C.1周内

D.2周以后

E.1月以后

题型:选择题

FIDIC的全体会员行为的基本准则中,正直性责任表现在( )。

A.在任何时候均为委托人的合法权益行使其职责,并且正直和忠诚地进行职业服务
B.在提供职业咨询、评审或决策时不偏不倚,正直和忠诚地进行职业服务
C.通知委托人在行使委托权时可能引起的任何潜在的利益冲突
D.不接受可能导致判断不公的报酬,正直和忠诚地进行职业服务

题型:选择题

境外企业制造的用于境内的锅炉,其制造许可证由()颁发。

A、国家质检总局

B、省级质量监督部门

C、境外政府

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