I prefer being outside.John says.将两句合为一句是否有时态变化？为什么？

John says that I prefer being outside .

John says he prefers being outside.这句合并后看主语啊，主语是John，那就用一般现在时

I prefer being outside.John says.
John says he prefers being outside.

John says he prefers being outside.
时态变化的话要看具体语境，像这个句子就是用一般现在时

John says that he prefers being outside.
没有时态变化,有人称变化.
因为你 给的主句 “John says” 是一般现在时,所以从句也是一般现在时.“John说”,所以是“他喜欢...”