Here is a question about this article: Being one of the four ancient capitals of China, Nanjing has always been a cultural centre attracting intellectuals from all over the country. In the Tang and Song dynasties, Nanjing was a place where poets gathered and composed poems reminiscent of its luxurious past; during the Ming and Qing dynasties, the city was the official imperial examination centre (Jiangnan Examination Hall) for the Jiangnan region, again acting as a hub where different thoughts and opinions converged and thrived.
What is the answer to this question: How many ancient capitals does China have in its history?
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So... four


Here is a question about this article: Even the Zhonghua Zihai does not include characters in the Chinese family of scripts created to represent non-Chinese languages. Characters formed by Chinese principles in other languages include the roughly 1,500 Japanese-made kokuji given in the Kokuji no Jiten, the Korean-made gukja, the over 10,000 Sawndip characters still in use in Guangxi, and the almost 20,000 Nôm characters formerly used in Vietnam.[citation needed] More divergent descendents of Chinese script include Tangut script, which created over 5,000 characters with similar strokes but different formation principles to Chinese characters.
What is the answer to this question: What is formed by Chinese principles? 
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So... Characters


Here is a question about this article: Serotonin is a neuromodulator involved in regulation of mood and behavior. Development in the limbic system plays an important role in determining rewards and punishments and processing emotional experience and social information. Changes in the levels of the neurotransmitters dopamine and serotonin in the limbic system make adolescents more emotional and more responsive to rewards and stress. The corresponding increase in emotional variability also can increase adolescents' vulnerability. The effect of serotonin is not limited to the limbic system: Several serotonin receptors have their gene expression change dramatically during adolescence, particularly in the human frontal and prefrontal cortex .
What is the answer to this question: Which neuromodulator is involved in regulation of mood and behavior?
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So...
Serotonin