spy upon的用法和樣例：
例句
- He often went to spy on her, but he never dared to let her see him.
他經常窺探她的行動，但從未敢讓她發現自己。 - One morning, this spy saw Jean Valjean, with an air which struck the old gossip as peculiar, entering one of the uninhabited compartments of the hovel.
有一天早晨，這個蓄意窺探的老婆子看見冉阿讓走進這座破屋的一間沒有人住的房裡去了，覺得他的神氣有些特別。
