The infinitive after question words

The infinitive after question words (LiF 21, p. 170)

Example: ... when to meet ...

To shorten the subclause you can use a question word + to + infinitive.

Have you told George when and where to meet us?

Have you told George when and where he should meet us?

I really don't know whether to go to the party or not.

I really don't know whether I should go to the party or not.

To use this the subject of the main clause and the subclause must be the same.

Infinitive after question words is often used after these verbs: to ask, to decide, to explain, to wonder, to learn, to know, to forget, to tell, to remember, to understand