若分式1x2-2x+m不论x取何值总有意义，则m的取值范围是（ ） A．m≥1 B．

完成句子。

     阅读下列各小题，根据括号内的汉语提示，用句末括号内的英语单词完成句子。

1. Don't bother to look for my old dictionary, Jason -it ____________ (出现) some day.   (turn)

2. I can't tell where Mary is, but she _______________ (可能去了) to meet her classmates, for

    they want to go to Yunnan to work as volunteers.   (go)

3. It was on the shelf ____________________ (我放鞋子的地方) that I found my car keys.

    How careless I was!   (put)

4. Hardly _____________________ (我们宣布仪式) open when the rain began to pour down. 

    (declare)

5. In the big fire the woman saved a little boy but lost her son. When asked if she regretted

    _______________ (没有救) her son, she said she made the right choice.   (save)

6. Hello! Is that ABC company? Could I speak to ___________________ (负责……的人)

    the International Sales,please?        (whoever)

7. He was absent again, which ________________ (使得我们困难) to carry on with the work.   (make)

8. As is reported, Chen Guangbiao, known as Chief Charitarian in China ("中国首善"),

    ______ (捐献了) billions to helping people in disaster-stricken areas these years.  (contribute)

9. __________ (在水少的地方), it is hard or even impossible to develop good farming.   (where)

10. When Xu Benyu graduated from college in 2003, he chose to teach in a mountainous area of

    Gui Zhou province when he ________________ (本可以享受) an easy city life.        (enjoy)

根据哪项可大致判断肠道杆菌的致病性（）

A.分解葡萄糖

B.分解乳糖

C.分解麦芽糖

D.分解甘露糖

E.分解蔗糖

恶魔效应：是指由于对人的某一品质，或对物品的某一特性有坏的印象，会使人对这个人的其他品质，或这一物品的其他特性的评价偏低。
下列各项中，属于恶魔效应的是( )。

A．小博小时候曾被狗咬伤过，从此以后他看到狗就感到特别害怕
B．小伟平时十分调皮，王奶奶不让自己的孙子和小伟来往
C．小军上班经常迟到，老板认为他工作态度不认真，即使能力突出也一直没有重用他
D．小宁的学习成绩一直不好，妈妈认为他以后一定考不上大学

某二叉树共有60个叶子结点与50个度为1的结点，则该二叉树中的总结点数为( )。

A．148

B．169

C．182

D．198

写出高炉冶炼中碱金属的富集循环现象。