an expert in radio communications 无线电通信专家

He's an expert at getting served in a crowded bar. 对如何在拥挤的酒吧里及时受到招待，他是个行家。

He's an expert skier. 他是个滑雪高手。

Over the years we've become quite expert at dealing with these sorts of problems. 这几年来我们在这些问题的处理上变得得心应手。

The British royal family are still less than expert in handling the media. 英国皇室现在还是不大会对付媒体。