n.间谍;密探;
vt.看见;秘密监视;精心调查;
vi.当间谍;从事间谍活动;暗中监视;详察;
例句:
a police spy
警方密探
He had his wife spied on for evidence in a divorce case.
他请人秘密监视自己的妻子,为离婚案搜集证据。
East and West are still spying on one another...
东西方仍在互相进行间谍活动。