无偿献血的无偿原则也是献血的一条根本原则。献血的无偿原则，反映了（）。 A.献血是一

TIA的好发年龄是（）

A.70～80岁

B.30～40岁

C.40～50岁

D.50～70岁

E.80～90岁

完形填空。

The first event of my life to be printed into my memory occurred when I was three. My mother stands, working in the  1   and then glances at me with a   2   smile. Two feet down the table, I knock on a chair with a bowl and a spoon,   3   my own invisible (无形的) powder. We wear   4   dresses, mine the leftover   5   from hers, sky blue-mommy's favorite color. I am her shadow.      However, by 14 I could not   6   my mother. All that I heard every day was no.I wanted to dye my hair and she said no. I wanted to   7   late with my friends and she said no. I didn't understand why she said no. She was trying to  8   me from aches and pains and mistakes   9   in her teens. Several years later, I finally understood her, but it was too late. She became ill. I cried and  10  ,"Don't take her, God, please! She is my mother, my mommy , the woman who gave me life. All my years,   11   the bad times and the good, she has been there,  12   to me forever by an invisible umbilical cord (脐带) that lasts longer after birth." But this cord, this love could do nothing to stop the cancer from  13  .       A few years later  14   I myself lay in the hospital bed, my newly born daughter was   15   in my arms. cried and smiled and prayed. Please help me to   16   her into a wonderful girl. And looking down   17   her eyes, I could see the message they held, "Your   18   would be proud."      I stand in the kitchen now, and these thoughts flashed through my mind. I glance at my young daughter. A    19   feeling rushes through my soul as I take in the familiar  20  . I am my mother's shadow.

( ) 1. A. kitchen     ( ) 2. A. lovely      ( ) 3. A. preparing   ( ) 4. A. same        ( ) 5. A. material    ( ) 6. A. stand       ( ) 7. A. keep up     ( ) 8. A. save        ( ) 9. A. watched     ( )10. A. screamed    ( )11. A. through     ( )12. A. connected   ( )13. A. spreading   ( )14. A. when        ( )15. A. placed      ( )16. A. change      ( )17. A. for         ( )18. A. daughter    ( )19. A. warm        ( )20. A. saying      B. dining room B. lively     B. mixed      B. similar    B. clothes    B. agree      B. keep on    B. warn       B. liked      B. said       B. in          B. shared     B. growing    B. before     B. given      B. support    B. through    B. mother     B. strange    B. scene      C. sitting room   C. loving         C. mixing         C. different      C. dress          C. know           C. stay up        C. help           C. heard        C. shouted      C. on             C. concerned      C. escaping     C. since          C. thrown         C. bring          C. up             C. children       C. painful        C. drawing      D. garden      D. horrible    D. prepared    D. matching    D. clothing    D. realize     D. stay out    D. stop        D. experienced D. prayed      D. within      D. joined      D. moving      D. then        D. taken       D. raise       D. into        D. friends     D. exciting    D. paint

EH油站配置了两台EH油泵，其形式为（）。

A、螺杆式；

B、叶片式；

C、高压变量柱塞式；

D、齿轮式。

回报规范对维护稳定的人际关系具有重要的作用。

(12分)某同学为了探究锌与硫酸反应过程中的速率变化，他在100mL稀硫酸中加入足量的锌粉，标况下用排水集气法收集反应放出的氢气，实验记录如下(累计值)：

(1)哪一时间段(指0～1、1～2、2～3、3～4、4～5min)反应速率最大______________，原因是______________________________________________。

(2)哪一时间段的反应速率最小________________，原因是___________________。

(3)求2～3分钟时间段以硫酸的浓度变化来表示的该反应速率(设溶液体积不变，要写出计算过程)______________________________________________________。

(4)该同学在用稀硫酸与锌制取氢气的实验中，发现加入少量硫酸铜溶液可加快氢气的生成速率。请回答下列问题：

①上述实验中涉及到的离子反应方程式有                                            

                                      ；

②硫酸铜溶液可以加快氢气生成速率的原因是                               ；

③实验室中现有Na₂SO₄、MgSO₄、Ag₂SO₄、K₂SO₄等4种溶液，可与实验中CuSO₄  溶液起相似作用的是                 ；

④该同学通过实验进一步研究了硫酸铜的量对氢气生成速率的影响。该同学最后得出的结论为：当加入少量CuSO₄溶液时，生成氢气的速率会大大提高。但当加入的CuSO₄溶液超过一定量时，生成氢气的速率反而会下降。请分析氢气生成速率下降的主要原因

                                          。