How have I changed

[suprunp]

“It is not the same,” Fuka-Eri said. “You changed.”
“I changed,” Tengo repeated.
Fuka-Eri nodded.
“How have I changed?”
(H. Murakami; 1Q84)


Uses of the Past Simple Tense
- when the action clearly took place at a definite time even though this time is not mentioned:
How did you get your present job?
(Змиева (Zmieva); Practical English Grammar Handbook)
This is a handbook from when I studied at my university.


Apart from what is said in the handbook I (we) was taught categorically that if one begins a question with the word "how" one must not use perfect tenses at all.
I dare to suppose that this is not quite right and maybe the way it should be explained is slightly different where you teach or study.
Am I right?

(I have given the extract from "1Q84" as an example that, in my book, shows a situation in which the speaker does not know a definite time (or thinks it was a gradual process) and, therefore, is free to use the present perfect.)

Thanks.

[Rover_KE]

There is nothing at all wrong with 'How have I changed?'

Rover

[5jj]

“It is not the same,” Fuka-Eri said. “You changed.”
“I changed,” Tengo repeated.
Fuka-Eri nodded.
“How have I changed?”

This is fine. Fuka-Eri is in effect saying, "How am I different now as a result of this change?"

Uses of the Past Simple Tense
- when the action clearly took place at a definite time even though this time is not mentioned:...How did you get your present job?

That is fine.

I (we) was taught categorically that if one begins a question with the word "how" one must not use perfect tenses at all.
That is not true.

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