（）适应于高扬程，小流量及高温、高粘度的介质输送。A.压缩机 B.离心泵 C.旋涡泵

阅读理解。

     John lived with her mother when he was young.  He didn't know who his father was. The woman did

some washing for the 'rich and could buy onl'y some bread for her son. So the boy was short and thin.

     One cold morning there was much snow in the streets. A car knocked the woman down and the

policemen took her to the hospital.  She didn't tell John that his father deserted (遗弃) her before he was

born until she died.  She left her son the name and address of his father.

     John found his father, Mr.  Brown, in another city.  He was one of the richest shopkeers and he had

to receive his son.  From then on the boy lived a rich life.  He ate all kinds of delicious food and wore

beautiful clothes.  But he didn't go to school and could not read or write.

     Once his father took him to a party.  He saw a newspaper lying on the floor and picked it up while

others were talking about a film.  He had a look at it and found a car's wheels (轮子) were upward

(向上). He called out,  "Oh, dear! An accident.

     All the people were surprised and began to read the newspaper.  But soon they all began to laugh.  

Do you know why?

1. John didn't know his father because___________.

A.  the man was rich            

B.  the man deserted his mother

C.  his mother left the man      

D.  the man didn't like him

2.  John was short and thin because___________.

A.  he didn't like sports

B. his parents were short, too

C.  he was often hungry when he was young

D. his mother never gave him food

3.   The woman told John who his father was___________.

A.  after she was knocked down by a car    

B.  before her son left

C.  before she was in hospital                

D.  before she died

4.  After John found his father, ___________.

A.  he was angry with the man  

B.  he started a rich life

C.  he wouldn't live with him    

D.  the man was bad to him

5.  The people at the party laughed at him because                        .

A. he held the newspaper upside down  

B. he wasn't polite

C. the newspaper was yesterday's        

D. he wasn't clever

小刚在化学实验室发现，盛放NaOH溶液的试剂瓶瓶口和橡皮塞上出现了白色粉末。小刚叫来小军和小红，共同探究这种白色粉末的成分。他们依据所学的化学知识，对这种白色粉末的成分作了如下猜想

① 可能是NaOH； ② 可能是Na₂CO₃； ③ 可能是NaOH与Na₂CO₃的混合物。为了验证猜想，他们分别

做了下面的实验。

（1）小军取少量白色粉末溶于水，向所得溶液中滴加酚酞试液，溶液变为红色。由此小军认为白色粉

末是NaOH。请判断小军所得结论是否正确，并简述理由。

_______，____________________________________________________________________。

（2）小红取少量白色粉末溶于水，向所得溶液中滴加BaCl₂试液，有白色沉淀产生。由此判断白色粉末

中含有______。为了验证猜想③，小红继续向溶液中滴加BaCl₂试液至不再产生沉淀，然后过滤。你认

为她接下来还应进行的实验是_____________________________________________；在小红所做的实验中，若把BaCl₂溶液换成Ba(OH)₂溶液是否可行？请简述理由。_________，_________________________

______________________________。

（3）在一烧杯中盛有22.3g Na₂CO₃和NaCl组成的固体混合物，加43.1g水溶解，制成溶液。向其中逐渐滴加溶质质量分数为10%的稀盐酸，放出气体的总质量与所滴入稀盐酸的质量关系曲线如图所示：请根据题意回答问题：（H-1；Cl-35.5；Na-23；C-12；O-16）

①当滴加了73g稀盐酸时，放出气体的质量为                  g。当滴加稀盐酸至图中B点时，烧杯中溶液里的溶质是（写化学式）                         。

②当滴加了73g稀盐酸时（即A点时），烧杯中为不饱和溶液，试通过计算求出其中含溶质的质量分数。[计算结果保留一位小数]

环境管理体系中组织应建立文件程序，对( )进行监测和测量，保证监测活动按规定进行。

A．核心环境因素和非核心环境因素

B．与核心环境因素有关的运行与活动

C．可能具有重大环境影响的运行与活动的关键特性

D．环境的重要影响因素

慢性肺心病心力衰竭时，以下哪种情况下使用强心剂

A．感染已控制，利尿剂无效

B．心率大于120次/分

C．明显气急发绀

D．两肺底湿性啰音

E．肺动脉高压

在以下禾谷类作物中，顶端优势最强的是（）。

A.玉米

B.小麦

C.油菜

D.棉花