/ 'elΙfənts/ can help people do heavy work. A.Elephants B. Element C. Elements D.Elephants 查看更多

 

题目列表(包括答案和解析)

请仔细阅读题中的学生情况说明,从A—F中选出能解决他们问题的恰当建议。(有一项多余)

A. Emily often feels tired and seems to be lack of energy.

B. Jeff spent his summer vacation on the beach and got serious sunburnt.

C. Kate has poor eyesight and she can’t see clearly at night.

D. Tony sometimes feels pains in his bones and he has loose teeth.

E. Luke is so careless that he often gets hurt. And it takes a long time for his wound to heal.

F. Linda feel nervous before the new people.

  1.Vitamin A

What can high-vitamin A foods do for you?

be great for night vision

help you see in color

help your grow properly and aids in healthy skin

﹡ vitamin A in carrots helps you see at night

    2.The B vitamins

What can the B vitamin do for you?

help make energy and set it free

help make red blood cells which carry oxygen(氧气) throughout your body

﹡ The B vitamins in leafy green vegetables help your body make protein(蛋白质)and energy.

    3.Vitamin C

What can vitamin C do for you?

keep body tissues(组织) in good shape

help you heal when you get hurt

help your body resist infection

﹡ Vitamin C in oranges helps your body heal if you get a cut

    4. Vitamin D

What can vitamin D do for you?

help keep your bones strong and healthy

help keep your teeth strong and healthy

help your body absorb the amount of calcium(钙)

﹡ Vitamin D in milk helps your bones and teeth.

 "         5. Vitamin E

What can vitamin E do for you?

protect your skin from ultraviolet(紫外线) light

protect you lungs from becoming damaged by polluted air

help make red blood cells

﹡ Sunflowers seeds are the richest in Vitamin E

 

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假如你是Li Lei, 下面是一封你的笔友Maria 给你发来的e-mail,请你根据e-mail 的内容给她写一封回信,与她交流看法,并帮她排忧解难。
  提示词语:listen to, mother’s love, care about, communicate with, get along with, smile
写作要求:
(1)语句通顺,书写工整;
(2)可用所给提示词语,也可以适当发挥;
(3)词数在60—80词左右
Dear Li Lei,
  I’m afraid I’ve got a big problem recently. My mother talks too much to me. She always tells me, "Be careful while crossing the street." "Put on more clothes." "Did you do a good job at school?" and so on. I’m annoyed(烦恼)。What shall I do?  
Yours,
Maria
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---Eddie has     e-dog at home.

---Oh, really?


  1. A.
    the
  2. B.
    a
  3. C.
    an
  4. D.

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实验室用铜制取硫酸铜,将适量硝酸分多次加入到铜粉与稀硫酸的混合物中,加热使之反应完全,通过蒸发、结晶得到硫酸铜晶体。
(1)为了节约原料,硫酸和硝酸的物质的量之比最佳为:    ;为了吸收该反应中产生的尾气,请选择下列中合适的装置       

(2)为符合绿色化学的要求,某研究性学习小组进行如下设计:
第一组:以空气为氧化剂法
方案1:以空气为氧化剂。将铜粉在仪器B中反复灼烧,使铜与空气充分反应生成氧化铜,再将氧化铜与稀硫酸反应。
方案2:将空气或氧气直接通入到铜粉与稀硫酸的混合物中,发现在常温下几乎不反应。向反应液中加少量FeSO4,即发生反应,生成硫酸铜。反应完全后,加物质甲调节pH ,铁元素全部沉淀(一般认为铁离子的浓度下降到10-5mol·L-1,就认为沉淀完全),然后过滤、浓缩、结晶。
已知:Ksp[Cu((OH)2]≈10-22, Ksp[Fe((OH)2]≈10-16,  Ksp[Fe((OH)3]≈10-38
请回答下列问题:
如开始加入的铜粉为3.2 g,最后所得溶液为500 mL,溶液中含有铁元素0.005 mol。
①方案1中的B仪器名称是       
②为了使铁元素全部沉淀,应调节pH至少为_________。
③方案2中甲物质可选用的是             
A.CaOB.NaOHC.CuCO3D.Cu2(OH)2CO3 E、Fe2(SO4)3
④反应中加入少量FeSO4可加速铜的氧化,用离子方程式解释其原因        
第二组:过氧化氢为氧化剂法
将3.2g铜丝放到45 mL 1.5mol·L-1的稀硫酸中,控温在50℃。加入18mL 10%的H2O2,反应0.5h,升温到60℃,持续反应1 h后,过滤、蒸发浓缩、减压抽滤等,用少量95%的酒精淋洗后晾干,得CuSO4·5H2O 10.5g。
请回答下列问题:
⑤反应时温度控制在50℃~60℃不宜过高的原因是         
⑥本实验CuSO4·5H2O的产率为         

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In the mid 1990s, people started doing business on the Internet. At that time, there were two kinds of companies. First, there were traditional companies which sold things in stores. Then, there were Internet companies which didn’t have stores, they sold things only over the Net.
Traditional companies didn’t want to lose any business. Quickly, they created their own websites and began selling things over the Net. These are the so-called “brick and click” companies. Many stores are made of brick, and you click on your mouse to buy things with your computer. That’s where the name “brick and click” comes from.
By the late 1990s, e-businesses like Amazon.com, Buy.com, and eToys.com were in trouble. Their profits(利润) were not very high, and there was a lot of competition. Many of these businesses lost a lot of money, and in 2000, many e-businesses were out of business.
In the world of e-commerce(电子商务), companies are fighting for every dollar and every customer. Will brick and click companies win the war? Only time will tell.
【小题1】Many traditional companies created their own websites in               .

A.the early l990s B.the mid l990s
C.the late l990sD.1990s
【小题2】Why were Internet companies in a lot of trouble in the late 1990s?
A.Competition was heavy.
B.Their websites were bad.
C.They didn’t know what to sell.
D.Their profits were high.
【小题3】Which would be a brick and click company?
A.A clothing company with no website.
B.A bookseller with five stores and an Internet site.
C.A video seller with a big website but no stores.
D.A restaurant.

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