Metto i biscotti in un altro sacchetto, così non si rompono.

Metto is the 1st person singular present indicative of mettere (to put).

So:

• metto = I put / I’m putting
• base verb: mettere

In this sentence, Italian uses the present tense very naturally for an action happening right now, so metto can sound like either I put or I’m putting, depending on context.

Because Italian usually drops subject pronouns when they are not needed.

The verb ending already tells you who the subject is:

• metto = I put
• metti = you put
• mette = he/she puts

So Metto i biscotti... already clearly means I put / I’m putting the biscuits...

You could say Io metto i biscotti..., but that would usually add emphasis, contrast, or clarity, such as:

• Io metto i biscotti, tu prendi il pane.
  I’ll put the biscuits away, you take the bread.

Italian uses articles more often than English.

Here, i biscotti means the biscuits / the cookies, referring to a specific group of biscuits the speaker is handling.

In English, we often drop the article in situations like this, but in Italian it is very natural to include it:

• Metto i biscotti... = I’m putting the biscuits...

Without the article, biscotti would sound less natural in this sentence.

Also note:

• i = masculine plural definite article
• biscotti = plural of biscotto

Because un altro sacchetto is indefinite: it means another bag, not the bag.

Compare:

• in un altro sacchetto = in another bag
• nel sacchetto = in the bag

Also, in combines with definite articles:

• in + il = nel
• in + lo = nello
• in + la = nella

But it does not combine with un, so you simply say:

• in un sacchetto
• in un altro sacchetto

Because altro does not take an apostrophe after masculine singular un.

So the correct form is:

• un altro sacchetto

This is different from the feminine form:

• un'altra borsa

Why?

• un (masculine) is already the normal form, so there is no elision
• una (feminine) becomes un' before a vowel, so you get un'altra

So:

• masculine: un altro
• feminine: un'altra

Here così means something like:

• so
• this way
• so that

In this sentence, it introduces the result or intended result of the first action:

• Metto i biscotti in un altro sacchetto, così non si rompono.
• I’m putting the biscuits in another bag, so they don’t break.

It has the sense of by doing this, that problem won’t happen.

This is a very common Italian use of così.

Here rompersi means to break / to get broken.

So:

• si rompe = it breaks / it gets broken
• si rompono = they break / they get broken

In this sentence, si is not really reflexive in the English sense of the biscuits break themselves. It is part of the verb rompersi, which is commonly used when something breaks, especially by accident or through pressure.

So:

• non si rompono = they don’t break / they don’t get broken

This is the most natural way to express the idea for fragile things like biscuits, glasses, toys, etc.

Examples:

• Il bicchiere si rompe facilmente.
  The glass breaks easily.
• Le uova si rompono.
  The eggs break.

Because the subject is i biscotti, which is plural.

So the verb must also be plural:

• il biscotto si rompe = the biscuit breaks
• i biscotti si rompono = the biscuits break

This is just normal subject-verb agreement.

Italian often uses the present tense where English might also use the present, or sometimes where English could use the future depending on context.

Here così non si rompono means:

• so they don’t break
• so they won’t break

Both ideas are close in English.

Using the present in Italian makes the result sound immediate and natural: I do this, and as a result they don’t break.

You could also say:

• così non si romperanno

That means more explicitly:

• so they won’t break

But the original sentence with the present is very normal and idiomatic.

Yes, but it changes the structure a little.

• Metto i biscotti in un altro sacchetto, così non si rompono.
  I’m putting the biscuits in another bag so they don’t break.

• Metto i biscotti in un altro sacchetto per non romperli.
  I’m putting the biscuits in another bag so as not to break them.

The difference is:

• così non si rompono focuses on what happens to the biscuits
• per non romperli focuses more on the speaker’s intention not to break them

Both are possible, but the version with così non si rompono sounds very natural and conversational.

Italian word order is somewhat flexible, although the original sentence is the most neutral and natural.

Standard order:

• Metto i biscotti in un altro sacchetto, così non si rompono.

You could also say:

• Così non si rompono, metto i biscotti in un altro sacchetto.

But that sounds less neutral and more marked.

You could also move things around for emphasis:

• Metto in un altro sacchetto i biscotti, così non si rompono.

This is grammatically possible, but less natural in everyday speech.

So yes, word order can change, but the original version is the best everyday choice.

Not exactly.

• sacchetto = small bag, often plastic or paper
• borsa = bag in a broader sense, like a shopping bag, handbag, or tote
• pacchetto = packet/package/parceled pack

In this sentence, sacchetto is a good choice because it suggests a small bag used to hold the biscuits.

So un altro sacchetto sounds like another little bag / another bag, which fits the context well.