管井使用应注意哪些问题？

某化学兴趣小组对教材中“测定空气里氧气含量”的实验（见图I）进行了大胆改进，设计图（Ⅱ）（选用容积为45mL的18×180mm的试管作反应容器）实验方案进行，收到了良好的效果．请你对比分析下面图I、图Ⅱ实验，回答下列有关问题：

（1）图I实验中红磷燃烧的实验现象是：______，

等A瓶冷却后打开止水夹，现象为：______．变化过程的文字表达式为______．反应基本类型为：______（“化合反应”或“分解反应”）

（2）图Ⅱ实验的操作步骤如下：①点燃酒精灯．②撤去酒精灯，待试管冷却后松开弹簧夹．③将少量红磷平装入试管中，将20mL的注射器活塞置于10mL刻度处，并按图Ⅱ中所示的连接方式固定好，再将弹簧夹紧橡皮管．④读取注射器活塞的数据．你认为正确的实验操作顺序是______（填序号）．

（3）图Ⅱ实验中，注射器活塞将从10mL刻度处慢慢前移到约为______mL刻度处才停止．

（4）对照图I、图Ⅱ实验，图Ⅱ实验的装置有何优点？（回答一点即可）______．

There are many best –selling authors in Europe and one of them is a 15-year –old girl from Paris. She is Flavia Bujor. Flavia is selling more books than people three times her age.

She started writing her novel at the age of 12. At 14, she had her book published. Her best-seller is called The Prophecy of Stones (<<石头的预言>>). The Prophecy of Stones is a story about a girl in hospital. In the story, the girl imagine another world and in that world three heroines work together to save their land with magical stones. So far, the book has sold 20,000 copies in France and Italy and 30,000 in Germany! Flavia Bujor says that “writing is my passion(最爱)”, but she still enjoys being 15. She takes piano lessons and likes hanging out with friends. The French girl plans to spend her money on her college education,

50.The Prophecy of Stones tells about things happening in _______________.

A. our real world   B. an imaginary world   C. the outer space  D. both A and B.

51.The underlined sentence in the last paragraph means ______________.

A. She likes to do things people of her age do 

B. She feels happy to be a 15- year –old best –selling author.

C. She does not wish to grow up.

D. She thinks15 is the best age for her as an author

52.What may be the best title for the article?

A. The Prophecy of Stones attracts most attention.

B. A 15-year –old girl becomes best-selling author.

C. Good school girl and best – selling author

D. Young author has more readers.

53.This passage probably appears _____________.

A.    in a story book               B. in a textbook

C.    in a newspaper               D. in a fashion magazine

能够确定粘性土液限的方法有（）。

A.收缩皿法

B.搓滚法

C.蝶式液限仪试验

D.液塑限联合测定法

蓄电池是通信电源系统中，直流供电系统的重要组成部分。在市电正常时，与整流器并联运行，起（）作用；当市电异常或在整流器不工作的情况下，则由蓄电池单独供电，担负起对全部负载供电的备用作用。

数量指标按其反映的时间计量特点不同，可分为（）和（）。