鳞甲目兽类牙齿的特征是()。A、无牙齿 B、有牙齿 C、为同型齿 D、为异型齿

题型:单项选择题

问题:

鳞甲目兽类牙齿的特征是()。

A、无牙齿

B、有牙齿

C、为同型齿

D、为异型齿

考点:生物学哺乳纲哺乳纲题库
题型:单项选择题

(10分)随着工业的迅速发展,产生的废水对水体的污染也日趋严重。通过控制溶液的pH对工业废水中的金属离子进行分离是实际工作中经常使用的方法。下表是常温下金属氢氧化物的Ksp(沉淀溶解平衡常数)和金属离子在某浓度下开始沉淀所需的pH(表中浓度为相应pH时溶液中有关金属离子产生沉淀的最小浓度;当溶液中金属离子浓度小于10-5 mol•L-1时通常认为该离子沉淀完全)。

金属离子KsppH(10-1 mol•L-1 pH(10-5 mol•L-1)
 Fe3+ 4.0×10-38 2.7  3.7
Cr3+  6.0×10-314.35.6
Cu2+2.2×10-20 4.76.7
Ca2+ 4.0×10-5 12.3  14.3
(1)某厂排出的废水中含有Cu2+和Fe3+,测得其浓度均小于0.1 mol•L-1。为除去其中的Fe3+,回收铜,需控制的pH范围是_______________________________。

(2)为了处理含有Cr2O72-酸性溶液的工业废水,采用如下方法:向废水中加人适量NaCl,以Fe为电极进行电解,经过一段时间,有Cr(OH)3和Fe(OH)3沉淀生成排出,从而使废水中铬含量低于排放标准。

①Cr2O72-转变为Cr3+的离子方程式为______________________。

②pH对废水中Cr2O72-去除率的影响如图。你认为电解过程中溶液的pH取值在______范围内对降低废水中的铬含量最有利,请说明理由:_________________________________。

[注:去除率(%)=[(c0-c)/co]×100%,式中:co—处理前废水中Cr2O72-浓度,c—处理后废水中Cr2O72-的浓度]

(3)沉淀转化在生产中也有重要应用。例如,用Na2CO3溶液可以将锅炉水垢中的CaSO4转化为较疏松而易清除的CaCO3,该沉淀转化达到平衡时,其平衡常数K=_________(写数值)。[已知Ksp (CaSO4)=9.1x10-6,Ksp (CaCO3)=2.8×10-9]

题型:单项选择题

第二节完形填空(共20小题,每小题1分,满分20分)

阅读下面短文,掌握其大意,然后从36—55各题所给的四个选项(A、B、C和D)中选

出最佳选项,并在答题卡上将该项涂黑。

A gentle breeze blew through Jennifer’s hair.The golden red sun was  36 She was on the

beach,looking up at the fiery ball.She could hear nothing but the waves and the  37  flying up

in the sky.

The  38   relaxed her.After all she’had been through,this is what she needed.

She wondered how her parents would  39 ,when she got home after the three days she was missing.She kept on walking,  40  herself-to bungalow 163,where’she spent every summer holiday.Just in a few hundred meters she would have been  4 1  in her house.

It was really getting dark now ,the sun had set a few minutes before and it was getting  42 too.She imagined having her favorite  43  on:it kept her really warm.This thought   44 when she finally saw her front door.45 had taken care of the outside garden for a few days.She was  46 :her father was usually so strict about keeping everything clean and tidy,and now.. It all seemed  47 :.She couldn’t understand what was  48  on.

She entered the house.First.she went into the kitchen where she saw a(n)  49  written by her father,reading“'Dear Ellen,there is some coffee ready,1 went looking.”Ellen was her mother but where was she?On the right side ofthe hallway was her parents  50  She went in.Then she

saw her.Her motther lying on the bed,sleeping.Her face looked so tired,  51   she hadn’t slept for days.Jenny would have wanted to wake her up,but she didn’t  52  her tired mother.So Jenny just fell asleep  53    her.When Jennifer woke up something was different…she wasn’t in her mother’s room.She was in her cozy bed in her pajamas.

It  54  so good being back home.Suddenly she heard a voice,‘'Are you feeling better now,

dear?You now you got us very,very  55 .”

36.A.rising        B.setting         C.shining         D.1anding

37.A.seagulls      B.angels         C.parrots          D.rainbows

38.A.condition     B.style           C.atmosphere      D.weather

39.A.resist        B.reflect          C.reject           D.react

40.A.directing     B.assisting         C.allowing        D.commanding

41.A.tired        B.thrilled          C.safe            D.anxious

42.A.hot         B.warm           C.cloudy           D.cold

43.A.cap        B.sweater         C.slippers          D.jewelry

44.A.aroused     B.fipeaed           C.disappeared      D.formed

45.A.Nobody    B.Somebody       C.Everybody       D.Anybody

46.A.terrifled    B.shoeked         C.excimd          D.disturbed

47.A.declined    B.deployed         C.designed         D.deserted

48.A.going      B.marching          C.coming         D.taking

49.A.e-mail     B.composition        C.1etter           D.note

50.A.study      B.bed               C.room           D.balcony

51.A.in that     B.asif               C.now that         D.even if

52.A.force      B.comfort           C.interrupt          D.blame

53.A.around     B.beneath           C.beside            D.over

54.A.sounded    B.1ooked           C.seemed           D.felt

55.A.annoyed    B.scared           C.confused          D.embarrassed

题型:单项选择题

何谓“物流标准化”?

题型:单项选择题

某商业企业属于增值税小规模纳税人,5月份有关购销业务如下:(1)购进服装100套,进价150元/套,取得普通发票,价款已付;另支付进货运费200元,取得运输单位开具的运输发票;(2)购入办公设备,取得普通发票,注明价款5500元;(3)销售服装80套,售价412元/套,开具普通发票上注明价款32960元,价款已全部收到;(4)转让厂房,取得转让收入100000元。(说明:有关票据在本月均通过主管税务机关认证并申报抵扣;月初增值税留抵税额为0。)

下列各项说法正确的是()

A.该企业外购服装可抵扣的进项税额为0

B.该企业外购服装发生的运费可抵扣的进项税额为14元

C.该企业购入办公用品可抵扣的进项税额为165元

D.该企业可按3%的征收率计算可抵扣的进项税额

题型:单项选择题

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