根据所学过的知识，填写我国北方地区和南方地区有代表性的地理事物

如图，一对对置的枕形导体A和B分别安放在两根绝缘支柱上，AB彼此接触，操作如下：

第一步：将带正电荷的物体C移近导体A，然后保持不动，____（A或B）端出现负感应电荷，另一端出现正感应电荷。

第二步：取一根导线，连接A的左端和B的右端，导线中____（有或无）瞬间电流，撤走导线。

第三步：把A、B分开，再将物体C移去。

第四步：再取一根导线，连接A的左端和B的右端，导线中____（有或无）瞬间电流。

词在填入前需进行词形转换，每个单词只能用一次，每空只能写一词。

    Norman Bethune is one of the most famous ____ for Chinese people. He was not Chinese, but he gave his life to helping Chinese people.

    Norman Bethune was born in 1890, in Canada. He ____ a doctor in 1916. In 1938 he came to China. There were few doctors then, so he had to work very ____. Once, he worked for 69 hours without stopping, and saved 112 people. Although he cut his hand, he did not stop to ____ care of it. In the end, he died from the cut.

    Dr Bethune's work with the Chinese soldiers made ____ a hero in China. He will be remembered by Chinese people for ever.