The difficulty stems from the fact that while an externality may be seen as a cost to one group.

困难常常来自这样的事实，即一种外在因素对一部分人可视为成本。

youdao

The difficulty stems from the fact that while an externality may be seen as a cost to one group.

困难常常来自这样的事实，即一种外在因素对一部分人可视为成本。

youdao