Η αλοιφή βοηθάει πολύ, αλλά ο επίδεσμος είναι πιο χρήσιμος όταν περπατάω.

They both mean the, but they match the gender of the noun:

• η αλοιφή = the ointment / the cream
• ο επίδεσμος = the bandage

In this sentence, both articles are singular nominative, because both nouns are subjects of their clauses.

Because Greek nouns have grammatical gender. Every noun is masculine, feminine, or neuter, and the article and adjectives must agree with it.

So here:

• η αλοιφή is feminine
• ο επίδεσμος is masculine

This is not always based on real-world sex; it is just part of the grammar of the word. A good habit is to learn nouns together with their article:

• η αλοιφή
• ο επίδεσμος

Yes. Both mean helps.

• βοηθάει
• βοηθά

These are two common present-tense forms of the same verb in Modern Greek. βοηθάει often sounds a bit fuller or more conversational, but both are normal and correct.

Because πολύ here is an adverb, not an adjective.

It modifies the verb βοηθάει and means:

• a lot
• very much

So:

• βοηθάει πολύ = helps a lot

By contrast, πολλή is a feminine adjective and would have to describe a feminine noun:

• πολλή βοήθεια = a lot of help

A very common way to make the comparative in Greek is:

• πιο + adjective

So:

• πιο χρήσιμος = more useful

This is the most everyday pattern and works with lots of adjectives.

Greek also has comparative forms like χρησιμότερος, but πιο χρήσιμος is extremely common and natural.

Because the adjective must agree with the noun it describes.

Here, χρήσιμος describes ο επίδεσμος, which is:

• masculine
• singular
• nominative

So the adjective is also masculine singular:

• ο επίδεσμος είναι πιο χρήσιμος

Compare:

• η αλοιφή είναι πιο χρήσιμη = feminine
• το φάρμακο είναι πιο χρήσιμο = neuter

Because after είναι Greek normally uses a predicate adjective without an article.

So:

• ο επίδεσμος είναι πιο χρήσιμος = the bandage is more useful

That is the normal structure.

If you add an article, it changes the feel or meaning. For example, ο πιο χρήσιμος often means the most useful or the more useful one, depending on context. That is not what is happening here.

όταν means when and introduces a time clause:

• όταν περπατάω = when I walk

Here it describes a general or habitual situation: the bandage is more useful whenever the speaker walks.

So the sentence is not about one single moment only; it sounds like a regular experience.

Because Greek usually drops subject pronouns when the verb ending already shows who the subject is.

The ending -ω tells you it is 1st person singular:

• περπατάω = I walk / I am walking

So εγώ is not needed.

You could say όταν εγώ περπατάω, but that would usually add emphasis, something like when I walk as opposed to someone else.

Yes. Both are common and both mean I walk / I am walking.

• περπατάω
• περπατώ

In Modern Greek, many verbs have this kind of double form. περπατάω often sounds a bit more conversational, but both are standard.

This sentence uses a very neutral, straightforward Greek word order:

• Η αλοιφή βοηθάει πολύ
• αλλά ο επίδεσμος είναι πιο χρήσιμος όταν περπατάω

Greek word order is often more flexible than English, but this is a very natural default structure:

• subject + verb + other information

So for a learner, this sentence is nice because the order is quite easy to follow.

Because αλλά means but, and in Greek it is normal to put a comma before it when it joins two clauses.

So:

• Η αλοιφή βοηθάει πολύ, αλλά...

This is very similar to English punctuation in sentences like:

• The ointment helps a lot, but...

The accent mark shows which syllable gets the stress.

Roughly:

• η αλοιφή → a-loi-FI
• βοηθάει → vo-i-THA-i
• πολύ → po-LI
• αλλά → a-LA
• ο επίδεσμος → e-PI-des-mos
• είναι → I-ne
• πιο χρήσιμος → pyo HRI-si-mos
• όταν περπατάω → O-tan per-pa-TA-o

A few extra pronunciation notes:

• β sounds like English v
• αι often sounds like e
• ει often sounds like i
• χ is not an English h exactly; it is a harsher sound, especially in χρήσιμος

So the accents are very useful: they tell you where to stress each word.