I know Mike's wife. We're on a first-name basis.我认识麦克的太太，我们很熟。

We're on a first-name basis.我们很熟。例：I know this movie star. In fact, We're on a first-name basis.我认识这位影星，其实我们很熟。My English teacher is from America. We're on a first-name basis.我的英语老师来自美国，我们很熟。