watch常与动词keep连用，其后接for、on、over时，watch前可加也可不加不定冠词a，其后不接介词时，即keep watch作“站岗”“守业”解时，watch前不可加不定冠词。
watch例句
1、In spite of the watch set on the house, the thief escaped.
尽管这幢房子设置了看守人员，小偷还是逃跑了。
2、The shepherds watched their flocks.
牧羊人看守着自己的羊群。
3、I could sit and watch the river all day long.
我可以整天坐在这里看那条河。
4、You need to reset your watch to local time.
你需要把表调整到当地时间。
5、By my watch it is two o'clock.
我的表是两点钟。