To work hand in glove的意思是密切合作。我们来举个例子吧：

The local police are working hand in glove with the FBI to find the bank robbers.当地的警察正在和联邦调查局密切合作设法找到那些抢劫银行的罪犯。

Hand in glove这个词汇也经常用在反面的场合，形容一些人合谋犯罪等。下面就是一个例子：

I read in the paper about this customs officer they arrested at the airport. They caught him working hand in glove with a gang of smugglers to bring diamonds into the country without paying duty.

我在报纸上看到有关那个在机场被逮捕的海关官员的消息。他们发现他和一些走私者密切合作，把钻石带进来而不缴关税。"