准确性

Tom and Mike were good friends. Sometimes they were kind to each other, and sometimes they were not. But all of their classmates said they were like brothers.

One day they went out for a walk together. At noon they were very hungry and they went into a restaurant to have lunch. The waiter came up to them and asked, “What can I do for you?”

“Please bring us two apples first.” said Tom.

When the waiter put two apples on the table, Mike took the bigger one at once. Tom got very angry.

“You are impolite, Mike. Why don’t you take the smaller one?” Tom said.

“But I am right.” Said Mike with a smile, “If I let you take first, which one will you choose?” “Of course I’ll take the smaller one.” Said Tom.

“Yes.” Mike said, “If you take the smaller one, the bigger one will still be mine,. Don’t you think so?” “Oh!” Tom couldn’t answer.

小题1:Tom and Mike were__________.

A. kind to each other all the time 

B. sometimes kind to each other

C. friends of different schools

小题2:Mike only thought about ______when they were having lunch.

A. himself             B. Tom             C. his friends

小题3:The waiter gave them_________.

A. two apples          B. two eggs        C. two oranges

小题4:Tom took the ______ apple.

A. better                  B. bigger          C. smaller

小题5:Who took the apple first?

A. Mike                B. Tom             C. Both Tom and Mike

下列表述中属于证的是( )

A．头痛

B．疟疾

C．感冒

D．肝阳上亢

E．发热

测电笔的作用是______．发电机是根据______现象制成的．

工业上“侯氏”制碱法制得的纯碱产品中常含有少量的氯化钠。某化学兴趣小组对某纯碱样品进行下列探究活动。

称取11g样品于烧杯中，加20.4g水将其溶解，然后逐滴加入一定质量分数的稀盐酸并不断振荡，发现刚开始时并无气泡，一段时间后才有气泡产生，这引起了他们的好奇。

查阅资料知道：首先发生的反应是： Na₂CO₃+ HCl===NaHCO₃+NaCl， 然后发生的反应是：NaHCO₃ +HCl===NaCl+CO₂↑+H₂O。

实验过程中，测得加入稀盐酸的质量和溶液总质量的关系如图甲所示。请你解决下列问题：

(1)根据上述信息，请在图乙坐标系中画出实验过程中产生CO₂的质量随滴加盐酸质量的变化曲线（不必计算具体数据）。

(2)计算样品中NaCl和Na₂CO₃的质量比。

(3)计算实验中恰好完全反应时所得溶液的溶质质量分数。

关于条件反射，下列哪项错误（）

A.后天形成，数量无限

B.具有极大的易变性

C.具有高度的适应性

D.可以脱离非条件反射独立形成

E.条件反射建立的过程就是学习记忆的过程