A is beneficial to us if we use it reasonably, and vice versa. vice versa本身就是反之亦然的意思,这里的确是要表达你说的那个意思,反之,并不是反过来的吧,应该是说否定其条件,结果自然也就跟着否定了,我查了牛津字典确定了一下,英文vice versa的意思used to say the opposite of what you had just said又查了'反之亦然'中文的意思,但是中文解释的说法不一,可惜我手头上没有汉语词典~~不好意思帮不到你了,我中文概念一直以为是这个形式~~