La meva germana em passa el tornavís, i jo agafo el martell de sota la taula.

In Catalan, possessives are very often used together with the definite article:

• la meva germana = my sister
• el meu pare = my father
• la nostra casa = our house

For an English speaker, this feels unusual because English normally does not use the with possessives. But in Catalan, article + possessive + noun is the normal pattern in many cases.

So la meva germana is the expected standard form.

Em is the weak pronoun meaning to me or me, depending on how English expresses it.

In this sentence:

• La meva germana em passa el tornavís

the idea is that your sister is passing the screwdriver to you.

So:

• em = to me
• passa = passes / hands
• el tornavís = the screwdriver

Catalan often uses these short object pronouns where English may simply use a normal object form like me.

In Catalan, object pronouns like em, et, li, ens, us, els usually go before the conjugated verb.

So:

• em passa = passes me / passes to me
• em dóna = gives me
• em porta = brings me

This is very normal Catalan word order. English puts me after the verb, but Catalan usually puts the pronoun before it.

Usually, no. Catalan often drops subject pronouns because the verb ending already tells you who the subject is.

• agafo already means I take
• so jo agafo is literally I take, but with the pronoun stated explicitly

Here, jo is likely used for contrast or emphasis:

• La meva germana em passa el tornavís, i jo agafo el martell...
• My sister passes me the screwdriver, and I take the hammer...

The presence of jo helps highlight the switch from my sister to I.

They are two different verbs:

• passar here means to pass / hand
• agafar means to take / pick up / grab

So the two actions are different:

• your sister hands you the screwdriver
• you take the hammer

This is a very natural pairing in Catalan.

Catalan uses definite articles quite a lot, often more than English does.

Here the objects are treated as specific, identifiable things in the situation:

• el tornavís = the screwdriver
• el martell = the hammer
• la taula = the table

English sometimes omits articles in contexts where Catalan keeps them, but in this sentence the definite articles are fully expected.

De sota la taula means from under the table.

Breakdown:

• sota = under
• de sota = from under
• la taula = the table

So:

• el martell de sota la taula = the hammer from under the table / the hammer that is under the table

In context, it refers to the hammer located beneath the table.

Because the sentence is identifying which hammer you take.

Compare:

• agafo el martell sota la taula
• agafo el martell de sota la taula

The second one is clearer and more idiomatic for I take the hammer from under the table.

De sota gives the idea of origin or location-as-source: the hammer is the one from under the table.

Without de, the phrase can sound more like it modifies the action or can be less precise depending on context.

The accent mark shows the stressed syllable.

• tornavís is stressed on the last syllable: tor-na-VÍS

In Catalan, written accents help show pronunciation and sometimes distinguish words. Here the accent tells you where the stress goes and also fits Catalan spelling rules.

Agafo is the 1st person singular present tense of agafar.

So:

• agafar = to take
• agafo = I take

This is a very common Catalan verb. Depending on context, it can mean:

• take
• pick up
• grab
• catch

In this sentence, pick up or take fits best.

Yes, to some extent. Catalan has some flexibility, especially for emphasis, but the given sentence is very natural.

For example:

• La meva germana em passa el tornavís
• La meva germana passa el tornavís a mi — possible, but less natural here
• Jo agafo el martell de sota la taula
• Agafo el martell de sota la taula — also very normal

The version you have is a good standard, everyday way to say it.

Normally, Catalan often does not use a comma before i if it simply joins two closely connected elements. However, a comma can appear when:

• the sentence is a bit longer
• there is a change of subject
• the writer wants a clearer pause

Here there is a shift from la meva germana to jo, so the comma is understandable and natural. You could also see the sentence written without the comma in some contexts.