He doesn't know ____ next.在how to do,what to do it,when to do和where to go中应该选什么?理由
问题描述：
He doesn't know ____ next.在how to do,what to do it,when to do和where to go中应该选什么?理由
似乎都可以,我觉得.
答
where to go
如果是how ,应该是how to do it
what to do
when to do it