Could you please tell me if all the following sentences mean the same thing?
1- When did you see her for the first time?
2- When did you see her first time?
3- When did you see her the first time?
4- When did you first see her?
5- When did you see her first?
Please delete sentence 2 completely. It’s not grammatical.
Sentences 1 + 3 could have the same meaning, but technically only sentence 1 is correct if you mean “for the first time ever/in your life”.
Sentence 3 could be referring to a situation where it is know that in a given period you saw her a number of times and it simply asks when the first of those encounters happened.
Or it might be asking what time a first appointment took place.
Sentence 4 seems to ask what was the earliest point in time that you saw her in a particular situation or at a particular place.
Sentence 5 --> I haven’t decided what I think of it yet. 8)
But, maybe we should go back to the “last time” stuff.
Maybe I misinterpretted what you were asking there. (Or maybe not. ;))
For these two questions, I personally would expect a time of day as the answer. In other words, these questions mean something similar to:
Q: “What time was that last appointment that you had with him?”
A: “It was at 8:30 on a Friday morning.”
That’s a very specialized sort of question. Is that what you intended?
The sentences I gave you (above) are much more general in meaning and would be answered with things such as:
“Two months ago”
“In February”
“Last weekend”
“Yesterday”
That’s why I said that they sounded more natural to me. They are more commonly used/needed. And they ask the question I thought you wanted to ask.