下列各句中，加线的成语使用恰当的一项是（  ）

They are talking _______ they were old friends

_______ of taking a bribe(贿赂), the official was being investigated.

Most of us know we should cut down on fat, but knowing such things isn’t much help when it ________ shopping and eating. [ ]

The life we were used to ________since smart mobile phones rushed in.