把下面的“成数”改写成百分数．

三成____；四成五____；六成三____；一成____

某实验小组对不同条件下的硝酸钾的溶解情况进行了以下实验：在甲乙丙三个烧杯中放入20g硝酸钾晶体，再分别加入50g冷水、热水与酒精，充分搅拌后（保持各自的温度不变），结果如图所示．

（1）甲烧杯中溶液是____ （填“饱和”或“不饱和”）溶液．

（2）由以上实验可得出结论：影响物质溶解度的因素有____ 、____ ．

（3）将乙烧杯中的溶液降温到t₁℃时，溶液恰好达到饱和状态．则t₁℃时，硝酸钾的溶解度是____ g/100g水．再往乙烧杯中加入10g水，改变温度至t₂℃时，溶液又恰好达到饱和状态，则t₁____ t₂（填“＞”、“＜”或“=”）．

   John is my best friend. We live in the same building. We study in the same school but not in the same class. We often play football together after school. We have been good friends for two years.
   John is tall and strong with black hair. He has a round face, a small nose and big, brown eyes. I like his eyes because they are always bright and smiling.
   John is always friendly and helpful. When I feel bored or unhappy, he tells me funny jokes and makes me laugh. He'll give me help when I need.
   John is very smart. He reads a lot of books. He is good at singing and acts very well. He would like to make people happy with his songs and performance when he grows up. I believe that he can become as popular as Jackie Chan and travel around the world in the future.

材料一：太宗皇帝真长策，赚得英雄尽白头。

──唐·赵嘏

材料二：

材料三：宋朝时注重发展文教事业，改革和发展了这项制度，对宋代社会产生了深远影响，在全国范围营造了浓厚的读书风气，造成了宋朝科技发达、文化昌盛、人才辈出的文治局面。

生活处处有物理，小明对家中的电饭煲进行研究．他关闭了家里其它用电器，只让电饭煲工作，观察了电能表（上面标有“3000R/kW•h”），请你帮助小明解决下列问题．

（1）电饭锅在加热状态时，开关S应与触点____ （选填“1”或“2”）连接；

（2）他发现正常加热了6min电饭锅就转为保温状态，在这6min内电能表转盘刚好转了300转，则该电饭锅的加热功率是____ W；

（3）如果该电饭锅正常加热消耗了6×10⁵J电能，如果这些能量全部用来给“48V 500W”电动车充电（不考虑能量损失），能使该电动车以10m/s匀速行驶____km．