lo

In a sentence

• Lo més important és l'amistat.

  The most important thing is friendship.

  Here, 'lo' precedes 'més important,' functioning as an article to form a superlative.

• Ho sé, perquè m'ho va dir lo Pere.

  I know it, because Peter told me.

  Here, 'lo' is used as a colloquial form before a name, functioning as a determiner.

• No entenc lo complicat que pot ser.

  I don't understand how complicated it can be.

  Here, 'lo' introduces a subordinated phrase, functioning as a nominalizer.