水域: waters, body of water...
祖先: ancestor, forebears...
退让: to move aside, to get out of the way, to back down, to concede...
无穷无尽: endless, boundless, infinite...
写字台: writing desk...
语言: language...
东道主: host, official host (e.g. venue for games or a conference)...
随手: conveniently, without extra trouble, while doing it, in passing...
教师: teacher...
