Learn Hardcore Russian: Если послушать этого инструктора внимательно, можно делать упражнения безопасно. - If you listen to this instructor carefully, you can do the exercises safely.

Russian often uses an infinitive without an explicit subject to express a general condition or instruction, similar to English “if you / one / we listen…”.

Если послушать этого инструктора внимательно… literally feels like:

“If (one) listen to this instructor carefully…”
The subject is understood as anyone in general (you, we, people).

This is a common impersonal construction in Russian:

Если хорошо позавтракать, будет легче работать.
“If you have a good breakfast, it will be easier to work.”

So the infinitive послушать replaces something like если вы послушаете / если мы послушаем etc., but keeps it neutral and general.

Why is послушать perfective, but делать is imperfective?

Aspect choice reflects what is being emphasized:

послушать (perfective) – a completed, whole action:
“to listen (properly / for a certain time / to the end).”
The idea: if you have listened to the instructor properly (once, as required)…
делать (imperfective) – an ongoing or repeated activity:
“to do, to be doing, to keep doing exercises.”
The idea: you can then (regularly, correctly) do the exercises safely.

So the structure is:

Condition: one complete act — послушать
Result: a process / repeated activity — делать упражнения

Why этого инструктора and not этот инструктор?

Because послушать takes a direct object in the accusative case.

Nominative (subject): этот инструктор – “this instructor (does something)”
Accusative (direct object): этого инструктора – “(listen to) this instructor”

In the sentence, the instructor is the one being listened to, not the one doing the action, so he must be in the accusative.

Is этого инструктора genitive or accusative here?

Formally it looks like genitive, but grammatically it is accusative.

For masculine animate nouns, the accusative singular form = the genitive singular form:

Genitive sg.: этого инструктора
Accusative sg. (animate): этого инструктора

Here, since послушать needs a direct object, the case is accusative, even though the form matches the genitive.

Why is it инструктора, not something with a preposition like к инструктору?

The Russian verb слушать / послушать takes a direct object in the accusative, not a prepositional phrase:

слушать музыку – to listen to music
слушать радио – to listen to the radio
слушать врача – to listen to (follow the advice of) the doctor
послушать инструктора – to listen to the instructor

So Russian says literally “listen instructor”, not “listen to instructor”.
Hence инструктора (accusative), not к инструктору.

Can the word order change? For example, Если внимательно послушать этого инструктора… or можно безопасно делать упражнения?

Yes, Russian word order is flexible, and these variants are natural:

Если внимательно послушать этого инструктора, можно делать упражнения безопасно.
Если послушать этого инструктора внимательно, можно безопасно делать упражнения.
Если внимательно послушать этого инструктора, можно безопасно делать упражнения.

All are grammatical. The differences are about rhythm and slight emphasis:

Putting внимательно earlier (внимательно послушать) slightly highlights listening carefully.
Putting безопасно before делать (безопасно делать упражнения) can slightly highlight safety.

But none of these changes the basic meaning.

What is the difference between можно делать упражнения and можно сделать упражнения?

Again, aspect:

можно делать упражнения (imperfective) –
“it is possible / allowed / safe to do exercises (in general / repeatedly / as an activity).”
можно сделать упражнения (perfective) –
“it is possible to complete the exercises (once, finish them).”

In the original sentence, the idea is about performing exercises in a safe manner as an activity, not about finishing them once, so the imperfective делать is more natural.

Who is actually doing the exercises? Who does можно делать упражнения refer to?

The construction можно + infinitive is impersonal and usually means:

“one can…”, “you can…”, “it is possible to…”

So можно делать упражнения безопасно implies:

“you can do the exercises safely”
“one can do the exercises safely”
“it’s possible to do the exercises safely”

The subject is not named; it’s generic. Context would tell you if it means “you (students)”, “we”, or “people in general”.

Could we say Если вы послушаете этого инструктора внимательно, вы сможете делать упражнения безопасно? Is it the same?

Yes, that sentence is correct and close in meaning.

Differences:

Если послушать… можно делать…
– more impersonal, neutral, instruction-like; fits manuals, general advice.
Если вы послушаете… вы сможете делать…
– more personal and explicit:
- вы is clearly “you”
- сможете emphasizes your ability (“you will be able to”).

The original sentence sounds a bit more like a general rule or guideline.

Why isn’t there a то after если, like Если послушать этого инструктора внимательно, то можно…?

Russian often uses the particle то in conditional sentences:

Если идти прямо, то выйдешь к парку.

But то is optional, especially in spoken and informal written language.

Если идти прямо, выйдешь к парку.
Если послушать этого инструктора внимательно, можно делать упражнения безопасно.

Adding то is possible here and stylistically a bit more formal or “bookish”:
Если послушать этого инструктора внимательно, то можно делать упражнения безопасно.

Can we use когда instead of если here? For example: Когда послушать этого инструктора внимательно, можно делать упражнения безопасно?

No, not in that form.

Когда with an infinitive like this is not natural in standard Russian.
Когда normally introduces a time clause with a finite verb:
- Когда вы внимательно послушаете этого инструктора, вы сможете делать упражнения безопасно. – “When you have listened carefully to this instructor, you will be able to do the exercises safely.”

Если + infinitive expresses condition (“if”), not time.
So for the original structure, если is correct; когда doesn’t work with the bare infinitive there.

What’s the difference between делать упражнения безопасно and something like упражнения будут безопасными?

делать упражнения безопасно –
Focus on how you perform the exercises: you do them in a safe way.
упражнения будут безопасными –
Focus on the nature of the exercises themselves:
“the exercises will be safe (not dangerous).”

In the original sentence, the idea is that your manner of performing the exercises will be safe if you listen carefully to the instructor, so the adverb безопасно modifying делать is the natural choice.

Could we use выполнять упражнения instead of делать упражнения? Is there any nuance?

Yes, you can say:

можно выполнять упражнения безопасно

Both are correct, but:

делать упражнения – more neutral, everyday, “do exercises”.
выполнять упражнения – a bit more formal / technical, like “perform exercises”, often used in sports, medicine, training instructions.

Meaningwise they are almost the same here; it’s mostly a stylistic choice.