Dělala jsem online test s možností 4 odpovědí:
By the end of today’s seminar I will _____ to each of you individually.
1, speak
2, have spoken
3, be speaking
4, have been speaking
Dala jsem SPEAK, správná odpověď je HAVE SPOKEN. Prosím o vysvětlení

Tou dobou už ta činnost bude vykonána.
Bližší vysvětlení najdete v tomto článku:
https://www.helpforenglish.cz/…dbudouci-cas

Já bych řekl, že 1, 2 a 3 jsou správně.

At the end of … I will speak ([spíš] promluvím si), I will be speaking (budu mluvit)

By the end of … Na konci semináře už budeme mít tuto činnost za sebou:

1. I will have spoken … (… budu “mít (pro)mluveno …”  ).
2. I will have been speaking … (… budu “mít mluveno” ) Jako učitel si dám záležet na tom, abych v mluvení na každého došel …

[Your Czech is better than mine ]

I thought “by the end” meant something like “before/near the end”. If the speaker wants to say he/she will speak to them not exactly at the end of the seminar, but certainly before it ends, is it wrong to say “I will speak to you by the end of the seminar.”?

In the same way people say: I will do it by the end of the week. etc?

I'll do it by the end of next week (nejpozději do konce …) = when the end of next week arrives, I will have done it, it will be done. (I might even do it tomorrow or the day after, and not wait till next week). I'd still expect “I'll have it done/ready/fi­nished/comple­ted by the end of next week”. I can't imagine a context in which “I will speak to you by the end of the seminar” could (normally) be said. I'll speak to you before the end of the seminar.

No results found for “will speak to you by the end” (Google)

Dan, sorry for the thread necromancy. It just occurred to me: in the case of “be”, is it OK to use the future simple tense?

I'll be back by June.

And what about “have”?

You'll have the book back by Monday.

but (I assume):

I'll have returned the book by Monday.

Yes, those three sentences are all fine.

Thanks, does it then have to do with the type of the verb (I thought of the stative ones but that is not the case)?

I'll be back by Monday

vs

I'll have returned by Monday.

I guess it is the same as in:

…after you have returned …after you are back.

Sorry to appear unhelpful, but I don't understand what the question is. Is it about meaning, grammar or what?

“I'll be back by Monday” will usually mean the same as “I'll have returned by Monday”. The difference is in the functional sentence perspective, in other words what main point is the sentence trying to convey?

• I'll be back by Monday answers the question “when will you be back?”
• I'll have returned by Monday answers the question “will you be here by/on Monday?”

As you can see, the functional perspective of these two questions (and therefore of the two answers) is different.

Trying to analyse individual sentences out of context is a nightmare. Context is hugely important in understanding how English is used. Because we have so many tenses, we need to have a clear idea of the time relations in the context. And we also need to understand the functional sentence perspective in the context. And with every noun, we need to consider whether it needs an article or not, and if so, which article? In order to decide that, we need to know if the noun is occurring as a “first mention” or if we know about it already in the context.

[ After you have returned, after you are back are much less common than when you have returned, when you are back – see the Ngram. ]

My bad, I did not really articulate the question clearly…I think it all boils down to the following: when deciding about the proper tense (future simple or future perfect), is the perfect aspect (completeness) the only rule? Because for some verbs, we generally do not need to express the completeness, or at least that is something I infer from the usage:

• I'll be back on Monday
• I'll have been back on Monday //still correct, unusual or wrong?
• I'll have it by tomorrow.
• I'll have had it by tomorrow //still correct, unusual or wrong?

Going to the sentence in the original question:

By the end of today’s seminar, I will have spoken to each of you individually.

but what about the following – I think it is correct but I cannot pinpoint why exactly (though I assume it is because needing to perform an action cannot be truly completed?):

I need to talk to each of you individually by the end of today’s seminar,

1. I'll be back on Monday
2. I'll have been back on Monday (see Future Perfect)
3. I'll have it by tomorrow.
4. I'll have had it by tomorrow

These are all correct in an appropriate context. In 2 and 4, the speaker makes an assumption that something will be done or complete at a point in the future.

By the end of today’s seminar, I will have spoken to each of you individually. Correct. I am talking about something that will be done or completed (speak to each of you) at a point in the future (by the end of today's seminar).

I need to talk to each of you individually by the end of today’s seminar. Correct. I am talking about a current action (need to talk to you) that I want to complete at a point in the future (by the end of today's seminar).

Thanks Dan. One more thing, if you do not mind:

I will be back by Monday. I will have been back on Monday.

Is there any actual difference between these (as both express that on Monday, I will have been back)?

With “I will be back by Monday”, my vantage point or perspective is now, and I'm looking forward now to a point in the future when I will be back, though (because of “by”) we don't exactly when I will get back: it could be on Monday or any time before Monday.

With “I will have been back by Monday”, my vantage point or perspective is a point in the future (“Monday”) when (as far as I can predict at the time I make the statement) I will be able to look back and see that the action (of me getting back) or new state (of me being back) has taken place.