保证方式没有约定或约定不明确的，按( )承担担保责任。 A．合同 B．连带保证

明明跑了450米，爷爷跑的米数相当于明明跑的2倍，爸爸跑的比明明和爷爷跑的总数还多850米。爸爸跑了多少米？

关于二次函数y=ax²+bx+c图象有下列命题：

（1）当c=0时，函数的图象经过原点；

（2）当c＞0时，函数的图象开口向下时，方程ax²+bx+c=0必有两个不等实根；

（3）当b=0时，函数图象关于原点对称．

其中正确的个数有（　　）

A．0个

B．1个

C．2个

D．3个

化学实验室开放日，小新和小红两同学在实验室中配制了如下四瓶溶液：饱和氢氧化钙溶液（澄清石灰水）、饱和碳酸钠溶液、稀盐酸、氢氧化钠溶液，准备进行有关实验，过后发现未将饱和碳酸钠溶液和氢氧化钠溶液的试剂瓶贴上标签，并已混淆，两位同学决定将这两瓶溶液鉴别出来．

提出问题：如何用氢氧化钙溶液和稀盐酸将碳酸钠溶液和氢氧化钠溶液鉴别出来？

猜想与假设：将混淆的两种溶液分别编号为A、B．假设A为饱和碳酸钠溶液，B为氢氧化钠溶液．

设计实验方案：两位同学分别设计出如下的鉴别实验方案：

方案I：取样滴加稀盐酸，判断A、B各是哪种溶液．

方案II：取样滴加饱和氢氧化钙溶液，判断A、B各是哪种溶液．

交流与讨论：选择方案______（选填“I”或“II”）进行试验，所选试剂与碳酸钠溶液反应的化学方程式为：

______

进行试验：请你参与下列实验过程：

（1）实验桌上放置有如下图所示实验仪器，小新说：本实验不必用到的仪器是：______、______和______（填名称）

（2）根据你所选择的实验方案填写如下实验报告：

实验步骤	实验现象	结论
______	A溶液______ B溶液______	原假设______（填“正确”或“不正确”）

（3）溶液鉴定完毕，同学们马上将两瓶溶液贴上标签，并检查各瓶溶液的瓶塞是否塞紧，小红解释道：若未将试剂瓶口塞紧，配制的四瓶溶液中______的溶液（选填一种）将与空气中的二氧化碳反应发生变质，写出这个反应的化学方程式：______．

阅读理解。

     A famous teacher was speaking to the students at our school. He began his lesson by holding up a

￡100 bill. Then he said to the three hundred students, "Who would like to have this ￡100 bill?" The

students began to put up their hands at once.

     Then he said, "I am going to give this bill to one of you, but first, let me do this." He then made this

bill into a ball. Then he said, "Who wants it?" Hands went into the air.

     "Well," he said, "What if I do this?" and he dropped it on the floor and stepped on it. He picked up the

dirty, crumpled bill and said, "Who still wants it?" Hands went back into the air.

     "My friends," he said, "You've learned a valued lesson today. No matter what I did to the money, you

still wanted it because it didn't go down in value. It was still worth ￡100.

     Many times in our lives, we're dropped, crumpled, and stepped on by the chances we take and the

things that happen to us. We feel as if we are worth nothing. But remember, no matter what has happened

to you, you will never lose your value: you are always valuable to those who love you. Your value doesn't

come from what you drop or whom you know,but WHO YOU ARE.

     You are special and valuable. Don't ever forget it!

1. The story happened ______.

A. when the teacher gave the students some advice on how to learn English.

B. when the students were having a meeting.

C. when the teacher gave the students a speech.

D. when the students were discussing something interesting with their teachers.

2. Even though the money was dirty, it _______.

A. went up in value

B. was worth much

C. didn't reduce in value

D. was still ours

3. The underlined sentence in the third paragraph means_______.

A. the students put up their hands again.

B. the students put down their hands.

C. the students agreed to what the teacher said

D. the students put their hands in front of them

4. Why did the famous teacher use a ￡100 at his lesson?

A. Because he wanted to give a lecture about money.

B. Because he was used to dropping a bill on the floor and stepping on it.

C. Because he was going to give the bill to one of the students.

D. Because he wanted to make the students know what the value was.

5. What lesson can you learn from the passage?

A.￡100 bill is worth the same no matter what you do with it .

B. All people love money most.

C. Your value doesn't change no matter what happens to you.

D. The value of money changes when it is made dirty.

根据我国《导游人员管理条例》规定，参加导游资格考试的人员应具备的条件有( )。

A．是中国公民

B．具有高中、中专或以上学历

C．具有适应导游需要的语言表达能力

D．具有较好的相貌

E．身体健康