请将下面这段话翻译成英文：
郑和是一位伟大的中国探险家和舰队指挥官。他主要进行了七次探险活动， 为中国皇帝探索了世界，并在新的区域建立了与中国的贸易联系。永乐帝(Emperor Yongle)想向世界其他国家展示中华帝国(the Chinese Empire)的荣耀与权力，同时还想与世界其他国家建立贸易联系。于是他任命郑和为首席特使,命他成立一个舰队去探索世界。郑和指挥了一个大型舰队，第一次航海时估计有超过200艘船，将近28000人。
参考答案:
Zheng He was a great Chinese explorer and fleet commander. His seven main expeditions explored the world for the Chinese emperors and established the trade links between China and new areas. The Emperor Yongle wanted to show off the glory and power of the Chinese Empire to the world. He also wanted to establish the business relations with other countries. So, he appointed Zheng He as the Chief Envoy and asked him to set up a fleet to explore the world. Zheng He commanded a large fleet, whose first voyage was estimated to have over 200 ships and nearly 28,000 men.