钩端螺旋体最适合的培养温度为（） A.35℃ B.28℃ C.25℃ D.42℃ E

金属在生产生活中应用广泛。

(1)最初输水管材用铸铁，目前多用塑料管和塑料金属复合管，输送热水一般用铜管。下列管材中，属于金属材料的是        (填字母序号，下同)。

(2)铁生锈的条件是      。将生锈的铁片放在硫酸和硫酸铜的混合溶液中，可能发生的置换反应的化学方程式是              、               。

(3)金属的回收和利用是保护金属资源的一种有效途径。

①废钢铁可回收重新冶炼，用一氧化碳还原氧化铁的化学方程式为                                                      。

②将铁粉和铜粉的混合物放入硝酸银溶液中，反应结束后，对剩余固体成分的判断正确的是         。

A．肯定有银

B．肯定有铜

C．可能有铁

D．可能是铁和银

阅读理解。

                                                      Prayer for My Mother

Dear God,

     Now that I am no longer young, I have friends whose mothers have passed away.I have heard

these sons and daughters say they never fully appreciated their mothers until it was too late to tell

them.

     I am blessed with the dear mother who is still alive.I appreciate her more each day. My mother

does not change, but I do.As I grow older and wiser, I realize what an extraordinary person she is.

How sad that I am unable to speak these words in her presence, but they flow easily from my pen.

     How does a daughter begin to thank her mother for life itself? For the love, patience and just plain

hard work that go into raising a child? For running after a toddler (学步儿童), for understanding a

moody teenager, for tolerating a college student who knows everything? For waiting for the day when

a daughter realizes what her mother really is?

     How does a grown woman thank for a mother for continuing to be a mother? For being ready

with advice when asked or remaining silent when it is most appreciated? For not saying:"! told you

so", when she could have voiced these words dozens of times? For being essentially herself-loving,

thoughtful, patient, and forgiving?

     I don't know how, dear God, except to bless her as richly as she deserves(应得) and to help me

live up to the example she has set.I pray that I will look as good in the eyes of my children as my

mother looks in mine

                                                                                                                            A daughter

1. We can infer from the passage that the author is            .

A. talkative and realistic          

B. reserved and appreciative

C. open-minded and responsible    

D. sensitive and independent

2. Compared with her friends, the author feels lucky because           .

A. she has her own lovely sons and daughters

B. she is excellent in bringing up her own children

C. it was too late to say thanks to her mother in her presence

D. she still has the chance to express her appreciation to her mother

3. What information can you get from Paragraph 4?

A. Mothers should offer advice rather than blame.

B. The sentence "I told you so" can be repeated if necessary.

C. The author is very thankful to her mother for her education.

D. Mothers can instruct their children whenever they want to.

4. The author's mother has all the following fine qualities except ______.

A. devotion                        

B. forgiveness

C. consideration              '      

D. self-protectiveness

纯受拉连墙件只能用于（）层以下房屋。

A、2

B、3

C、4

环烯醚萜类化合物多以苷的形式存在于植物体中，其原因是

A．结构中具有半缩醛羟基
B．结构中具有环状半缩醛羟基
C．结构中具有缩醛羟基
D．结构中具有环状缩醛羟基
E．结构中具有烯醚羟基

冲击试验的结果与样片的温度（）相关。