I'm already familiar with the imperative form of first conditional, for example:
tell me if you need something
alert the guards if you see anything suspicious.
but how about the use of second conditional in an imperative sentence? Is that even correct? For example:
if you needed something, you would tell me
-> tell me if you needed something.I would alert the guards if I saw anything
-> alert the guards if you saw anything / if you happened to see anything.
thanks
The whole point of the second conditional is to talk about a hypothetical consequence of a hypothetical situation: one that (as far as the speaker is concerned) isn't going to happen. For it to be a true second conditional, the tense of the consequence-clause is backshifted to indicate that the consquence is also hypothetical.
If you change the tense of the consequence-clause to an imperative, it is no longer a second conditional.
By using an imperative, the speaker is indicating that they are talking about a non-hypothetical consequence, and that could never be the consequence of a hypothetical situation.
Tell me if you needed something.
This sentence is grammatical, but it does not fit the template for a second condtional. It's only a second conditional if the verbs in both clauses are backshifted.
What it means is if you needed anything in the past, please tell me now.
Here's a situation where it might be used. A science teacher is preparing a practical exam, and wants to make sure that all of the required equipment and materials are available in the lab. The teacher asks a technician to do the dry-run. Once it is completed, the teacher might say to the technician "tell me if you needed anything [that wasn't available]". They are discussing a real situation that occurred in the past, not a hypothetical situation in the future.
