Learn Italian: Siccome lo studente ha l'influenza, è assente da una settimana. - Since the student has the flu, he has been absent for a week.

Siccome means "since" or "as" and is specifically used at the beginning of a sentence to introduce a reason. Perché (because) is almost always used in the middle of a sentence. To use perché, we would flip the sentence order: Lo studente è assente da una settimana perché ha l'influenza.

Why is the present tense (è assente) used when the English translation says "has been absent"?

In Italian, if a situation started in the past and is still continuing right now, you use the present tense plus the preposition da (which translates here to "for"). Because the student is still absent today, Italian uses the present tense è assente rather than a past tense.

Why is the article lo used in lo studente instead of il?

For masculine words, Italian uses lo instead of il when the word starts with an s followed by another consonant. Because studente starts with s plus t, it requires lo.

I see l'influenza means "the flu". Do illnesses usually take definite articles in Italian?