I've searched the relevent questions but they didn't include what I was looking for.
I have two questions about 'as if'. Q 1 is about grammar and Q 2 is about meaning.
Q 1: I know we use 'as if' when we want to say 'as would be the case if'. For example we say, "she behaves as if she wasn't here" to mean she acts in a way that makes you think she was'nt here, but we know that she's really here right now.
If we want to talk about the same situation but in the past, should we go one more tense back or not? Which sentence is right?
She behaved as if she hadn't been here.
She behaved as if she wasn't here.
Q 2: can we use 'as if' when we want to make a strong guess about what we infer is true? (You see in the first example above she is really here, but she makes you think she wasn't here. But here I intend to make a realistic inference)
For example, we see friend 1 and he seems to be sleepy so we infer that he might not have got enough sleep last night. So when we see friend 2 we share what we think must be true about friend 1. Can we say:
'he looked as if he didn't get (hadn't got) enough sleep.'
I put the bracket in my example because I'm not sure which one is gramatically correct (the problem I put in Q 1)