... you can't present perfect (or continuous) and past simple within a sentence.
As it stands, this rule is incorrect. In many cases it is acceptable and logical to mix past and present references in consecutive clauses
I lost my keys last week, but now I have found them.
This makes sense: A was true then, but B is true now.
This, however, does not make sense:
He has decided to go hiking, so I went hiking as well.
This sentence amounts to A was true then, because B is true now. The simple past describes a past event, your going hiking, but what the present perfect describes is not a past event, his decision, but a present state which is the result of a past event--his state of having decided. That present state cannot be the cause of the past event. The cause must be either a past event or a past state:
He decided (event) to go hiking, so I went hiking as well or
He had decided (state) to go hiking, so I went hiking as well.
The important thing is not to mix time references illogically.
As for the sentence in your friend's email:
Getting that email was such a pleasant surprise, because I was just thinking how I've been wanting to send you an email
There is no mixture of time references here, because the progressive construction "I have been wanting" marks a state, not an event, which may very reasonably be taken to continue into the present out of a past which is marked (by "just") as immediate. In effect, these pasts inhabit the same time frame as the present.
In any case, the "rules" are very loosely applied in informal discourse; see my discussion here. A casual email, which your friend probably dashed off in excitement, should not be held to the formal literary standards of coherence.
The relevant grammatical rules involved here are
- The Perfect auxiliary have must be followed by the past participle form of the next verb.
- Modal auxiliary verbs like will must be followed by the infinitive form of the next verb.
- Conjunction Reduction optionally deletes the first of two identical verbs following auxiliaries.
The question is what counts as "identical" for conjunction reduction.
And the answer is that "identical" means "identical in sound". Nobody would ever say this sentence, for precisely the reasons described in the answers and comments here. That is, this isn't a question about English; this is about English spelling and reading, which is technology, not linguistics.
The problem with this sentence is that it looks like it's OK, but it doesn't sound like it.
Take a verb like sing, sang, sung, with different infinitive (sing) and past participle (sung) forms.
Then both
- *He has or will sing that song
- *He has or will sung that song
are ungrammatical, no matter which form is used.
And that's why
- *He has or will read that book
is ungrammatical. It could only happen in writing; it's a cheat, like a sight rhyme. It really should be
- He has red or will reed that book
(spelled funnetikly)
because words pronounced differently can't do conjunction reduction.
And spelling doesn't count.
- No English grammar rule has anything to do with spelling or punctuation.
If you try verbs with identical infinitive and past participle forms, like the set of
monosyllabic final-t verbs like set, set, set; cut, cut, cut; or put, put, put:
- He has or will set the plan in motion.
- He has or will cut them some slack.
- He has or will put it on display in the main gallery.
These sound perfectly grammatical (if needlessly complex), to me. This despite the facts that
- the set, cut, or put following will must be an infinitive,
but
- the set, cut, or put following has must be a past participle.
The abstract grammatical category of the deleted verb seems to be irrelevant -- as long as they sound the same, they're identical. And as long as that's the case, you can delete the first one.
Best Answer
I think it helps to look at the etymology of born.
So it's origin is as a past participle, such as used in the passive voice, and that is strictly speaking the form it still has, but today when I say 'I was born in London' I don't usely think of it in the sense of 'my mother bore me' or 'I was born(e) in London by my mother'. That's what the OED mean by"virtually an intransitive verb".
On your other links: Cambridge talks of 'to be born' as the verb, which is ok. The Quora link says 'it is used' as an adjective. They mean it in the way a participle derived from a verb can be used as an adjective (e.g. I am tired).
As for the reverso link, it doesn't look right to me at all. I'd almost speculate that it's some kind of computer-generated table based on 'to burn'.