She will have arrived by now

[Nonverbis]

Please, have a look at the screenshot above.
It is English Grammar in use by Raymond Murphy.

this construction looks strange to me. It is taken from Appendix 4.
Will means as if future, but now means as if present.
Will is a modal verb. But if I'm not mistaken, Murphy didn't show this very construction in the main part of the textbook.

In the second edition unit 24 is dedicated tothis construction. But they all refer to the future like "The fil will already have started by the time we get to the cinema".

So, could you help me understand "She will have arrived by now".

 

[5jj]

Will here shows the speaker's certainty, not futurity.

She will be there - I am certain that she is there
She will have arrived - I am certain that she has arrived.

 

[emsr2d2]

View attachment 4116

Please no comma here have a look at the screenshot above.
It is from English Grammar In Use by Raymond Murphy (Appendix 4). (Put book titles in italics.)

This construction looks strange to me. [STRIKE]It is taken from Appendix 4.[/STRIKE]
"Will" [STRIKE]means as if[/STRIKE] can express the future, but [STRIKE]now[/STRIKE] here [STRIKE]means as if[/STRIKE] it refers to the present.
"Will" is a modal verb no full stop here but, if I'm not mistaken, Murphy didn't show this [STRIKE]very[/STRIKE] construction in the main part of the textbook. What do you mean by "the main part of the textbook"?

In the second edition, Unit 24 is dedicated to this construction no full stop here but they all refer to the future, like "The film will already have started by the time we get to the cinema".

[STRIKE]So,[/STRIKE] Could you help me understand "She will have arrived by now"?

Please note my corrections and comments above.

In that sentence, "She will have arrived" expresses a certainty. "I am sure that she must have arrived by now".

(Cross-posted with 5jj)