KY-250A型牙轮钻机行走末级链条，每条的节数为（）节。

中 * * * * 、中 * * 军委 * * 习 * * 在广东考察工作时强调，要继承和发展改革开放伟大事业，为中国的未来发展注入强大正能量。下列有利于增加正能量的有（ ）

①某市大力表彰见义勇为模范、孝老爱亲模范

②电视台大量播放渲染后宫勾心斗角、尔虞我诈的富斗剧

③新闻媒体为吸引受众，大肆宣扬社会阴暗面

④某省开展“乡村文明行动”

A．①②

B．③④

C．②③

D．①④

Have you ever seen the film Titanic? “Titanic” was one of the largest and finest ships in 1912. It hit an iceberg(冰山)on its first sailing from England to America and sank very soon, leaving a love story to the people. Do you know what an iceberg is?

The earth is round, like a ball. The top of the earth is the north. The bottom of the earth is the south. At the top and the bottom of the earth, there is a lot of ice. It is very cold there. Sometimes there is no sunshine for many months. There is ice everywhere all the time. Large pieces of ice fall into the sea. They don’t go to the bottom of the sea. They float(漂浮)near the top of the water. We call these large pieces of ice “iceberg”. Some icebergs are bigger than a tall building. Icebergs are dangerous for ships. Sometimes a ship hits an iceberg.

Then the ship sinks.

You can make a small iceberg. Put a piece of ice in a glass of water. Look ar it. The ice does not sink.

小题1:Titanic is the name of a film and it’s also the name of a _______.

小题2:Titanic sank ________ it hit an iceberg.

小题3:The __________ is very cold in North Pole(北极)and in South Pole.

小题4:At times we can’t see the ___ in North Pole and in South Pole for a long time.

小题5: Icebergs are made of large _________.

下列说法中有误的一项是( )。

A．现代的市场经济是政府干预和市场经济相结合的混合经济

B．现代市场经济的发展在很大程度上取决于“划分市场与政府的合理界限是一个持久的问题”的有效解决

C．市场经济和社会主义基本制度的结合是不可行的

D．社会主义市场经济是市场经济与社会主义基本制度的结合

重度肺动脉高压时，室间隔缺损分流方向主要为

A．室水平左向右分流
B．室水平右向左分流
C．室水平双向分流
D．室水平无分流
E．房水平分流

锅炉缺水事故有哪些现象？如何处理？