mare tranquillitatis

美

英

英英

un.	1. lunar lowland plain visible in the northeast quadrant of the Moon, approximately 873 km (543 mi) across. It was the site of the the first crewed lunar landing, made by Apollo 11 in 1969.

随便看

英汉双解词典包含2704715条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。