Gunpowder (huǒ yào 火药) was invented in China rest on variable interpretations of certain passages in ancient manuscripts. Few substances in history have had as profound an effect on human history as gunpowder, and its discovery was an accident.

Zu Chongzhi (zǔ chōng zhī 祖冲之) was a famous mathematician and scientist in ancient China. He lived in Southern and Northern dynasties (nán běi cháo 南北朝). When he was young, he had a broad range of interests, such as natural science and philosophy. And he was interested in mathematics, astronomy and machinery.

唱对台戏
Stage a rival show.

【发音】chàng duì tái xì

【释义】过去，两个戏班子为了抢生意，有时候会在同一时间上演同样的戏，称为唱对台戏。比喻采取与对方相对的行动，来反对或搞垮对方。
            In the past, in order to gain a good position in business, two drama companies would put on the same play in the same time. Now this phrase has the meaning that one acts like the opposite side to combat or break it down.

【例1】 他们和我们唱对台戏。
            They challenge us with opposing views.

【例2】 吉姆准备参加竞选总统，埃里克也参加，这两个好友现在唱起了对台戏。
             James is running for presidency, so is Eric. Now these two good friends have entered in rivalry.

History
The Southern and Northern Dynasties (nán běi cháo 南北朝)(420-589) refer to the period of more than one hundred years from the decline of the Eastern Jin (dōng jìn 东晋) (317- 420) to the foundation of the Sui Dynasty (suí cháo 隋朝) (581-618). It was an age of civil war and political confrontation between two powers, one in the north and the other in the south. However, it was also a time of flourishing in the arts and culture. Created orally by people in the wake of Yuefu Songs (yuè fǔ 乐府), Folk Songs of the Northern and Southern Dynasties (nán běi cháo mín gē 南北朝民歌) has also played an important role in both Chinese music and literature. 

     
The history of Liangzhu jade (liáng zhǔ yù 良渚玉) can be traced back to 4300 to 5000 years ago. Most Liangzhu jade items were excavated in Fanshan (fǎn shān 反山), Yaoshan (yáo shān 瑶山) in Zhejiang Province (zhè jiāng shěng 浙江省), Qianshanyang (qián shān yàng 钱山漾), Caoxieshan (cǎo xié shān 草鞋山) in Jiangsu Province (jiāng sū shěng 江苏省), and Shanghai (shàng hǎi 上海). The delicacy of Liangzhu jade is beyond praise.