How did you know what to do next?
How did you know what you should do next?
If you have any questions, keep asking me
[English cattle group]
I really don't know ( ).A.what to do the next B.what to do it next C.how to do the next
D.what to do next
d
I don't know what to do next
Please don't say it's through language sense,
Please specify the specific grammar
Interrogative + infinitive (to do) is a fixed collocation, and "what to do next" is the object of the verb know