Watch的意思

They returned with him a [b]watch [/b]or so later, and let him lie down.

蒙古人Bold作为Temur可汗的侦察先锋往西边侦察，发现所到之处无人生还，早就发瘟疫死光光了，于是他返回向Temur报告这个消息，结果Temur下令立即杀死所有的侦察兵，然后Temur遭天谴，被闪电击中而死，Bold乘乱赶紧逃跑，他一直瘟疫区跑，一直跑，一个人忍受孤独饥饿和寒冷在一片死寂的土地上一直走，后来在海边的一个沙滩上睡着的时候被阿拉伯人发现，并被他们带到埃及给卖了。他被卖给了一个奴隶贩子，这个奴隶贩子用低价买了他，然后给他好吃好喝，带着他和其他奴隶，穿越大洋来到了Mombasa，遇见了中国人的大船，把他卖给了中国人，中国人带上他们起航了。

这只大船正是由郑和领导的，Bold和一个黑人小孩Kyu关在一起，这个小孩后来被阉了，这句就讲的是，小孩被阉之后，被人带走了之后发生的事情。

Watch这个词在The Years of Rice and Salt这本书里多次出现，按照上下文应该是指一段时间长度，上网查了查，发现这个词的这种用法还挺古老的：

1）Nautical：
a. a period of time, usually four hours, during which one part of a ship's crew is on duty, taking turns with another part.
b. the officers and crew who attend to the working of a ship for an allotted period of time.
2） one of the periods, usually three or four, into which the night was divided in ancient times, as by the Greeks or Hebrews: the fourth watch of the night.