如右图所示电路，电源电压保持不变，R₁=4Ω，R₂=6Ω．

（1）开关S₁断开、S₂闭合时，电流表示数为1.5A，求电源电压；

（2）开关S₁、S₂都断开时，求电流表的示数；

（3）开关S₁、S₂都闭合时，电流表示数为2A，求R₃的阻值．

    Scientists wanted to know more about the moon. They thought the best way was to send men to the moon. The moon is about 384, 000 kilometres away from the earth. A plane can not fly to the moon because the air reaches only 240kilometres away from the earth. But something can fly even when there is no air. That's a rocket(火箭).

    How does a rocket fly? There is gas(气体) in the rocket. When the gas inside the rocket got hot enough, it will rush out of the end of the rocket. So it can make the rocket fly up into the sky.     

    Rockets can fly far out into space. Rockets with men have been to the moon. Several rockets with men have flown to another planet much farther away than the moon. One day rockets may be able to go to any place in space.

根据短文内容, 补全下文。(词数不限)

    The moon is about 384, 000 kilometres away from us. It is so far that a plane ____ it. Scientists wanted to reach the moon and ____ about it. But how could they get there? They thought hard and at last they found a ____ could get there.

    A rocket can fly because of the ____ in it. When the gas in it got ____, it will rush out of the end of the rocket and make the rocket ____. So it can get into space. Now rockets with men ____ the moon. We believe that one day rockets may ____ in space.

读下列材料，回答问题。

材料一：中国是泰国第一大贸易伙伴和最大客源国。北京时间2015年12月19日14时，中泰铁路奠基仪式开始，规划线路全长845公里，设计时速180公里，将全部使用中国技术、标准和装备。建成后与中老铁路连接，从昆明乘火车可直接到曼谷。

材料二：天然橡胶种植业是泰国经济的支柱产业之一，泰国十年橡胶发展计划始于2014年9月，这个计划旨在提高天然橡胶的品质和价格。

材料三：中泰铁路线路示意图(下图)

请选出下列句子排序正确的一项（   ）

①清代曹雪芹说他的《红楼梦》：“满纸荒唐言，一把辛酸泪。都云作者痴，谁解其中味！”

②此后，诗人杜甫也叹息“百年歌自苦，未见有知音”。

③宋代的黄庭坚则慨叹“世上岂无千里马，人中难得九方皋”。

④苦吟诗人贾岛更痛苦地说：“两句三年得，一吟双泪流。知音如不赏，归卧故山秋。”

⑤东汉诗人曾悲叹“不惜歌者苦，但伤知音稀”，说出了没有知音的苦闷。

⑥他们都异口同声地焦急地召唤着“知音，希望自己的作品能得到人们的赏识。