Learn Italian: Siccome c'è uno sciopero improvviso, non vado a lavorare. - Since there is a sudden strike, I am not going to work.

In Italian, when you put the reason at the very beginning of the sentence (like "Since..." or "Because..."), you use siccome. Perché is almost always used in the middle of a sentence. If you flipped the order here, you would say: Non vado a lavorare perché c'è uno sciopero improvviso.

Why is it uno sciopero instead of just un sciopero?

Because the masculine noun sciopero starts with an "s" followed by another consonant (the "c"). Italian uses the article uno (and the definite article lo) before these words to make them flow better and easier to pronounce.

Why is there an a in vado a lavorare?

The verb andare (to go), here conjugated as vado, requires the preposition a when it links to another verb in its dictionary form (the infinitive). The pattern is always andare a + [action], which translates to "going to do [action]."

Why does improvviso come after sciopero?

Improvviso is an adjective meaning "sudden." In Italian, most descriptive adjectives are placed directly after the noun they describe. So "a sudden strike" becomes uno sciopero improvviso (literally: "a strike sudden").