He also took exception to having been spied on.

他也厌恶被暗中监视。

《柯林斯英汉双解大词典》

She resented being spied on when she was sunbathing in the garden.

她因在花园里沐日光浴时被人偷看而愤恨。

youdao

However when the researchers spied on them, it turned out they checked their email every five minutes.

但是研究者的暗中调查却发现他们实际是5分钟查看一次。

youdao

For instance, they've spied on cheating husbands and wives in order to document extramarital affairs.

NPR: Gumshoes Cite More Cases, Hassles Post-Katrina

The East German secret police, the Stasi, spied on him, using his friends and contacts as informers.

ECONOMIST: Cold-war spies

He said sorry because a New Zealand law enforcement agency was judged to have illegally spied on Mr Dotcom.

BBC: Megaupload spying case brings New Zealand apology