Learn Hardcore Portuguese (Portugal): Eu estou cansado, pois estudei muito hoje. - I am tired, because I studied a lot today.

Pois is a causal conjunction meaning "because" or "since" that connects the result (feeling tired) to its cause (studying a lot). Unlike porque, which is often used in direct answers to questions ("Why are you tired? Because I studied a lot today."), pois typically follows the statement it explains and is usually preceded by a comma for clarity.

Why is there a comma before pois in the sentence?

The comma separates two independent clauses: the main clause (Eu estou cansado) and the explanatory clause (pois estudei muito hoje). In Portuguese punctuation, using a comma before causal conjunctions like pois helps clearly delineate the statement from its explanation, enhancing readability.

What tense is used in estudei, and why is it appropriate here?

Estudei is in the simple past tense (pretérito perfeito), which indicates a completed action. Its use is appropriate here because it shows that the studying was done earlier today and is now over—a completed event that explains the current state of being tired.

Why does the sentence use Eu estou cansado instead of Eu sou cansado?

In Portuguese, estar is used to describe temporary states or conditions, while ser is meant for more permanent characteristics. Since being tired is a temporary condition resulting from an activity (studying a lot), estou is the correct choice, accurately communicating that the speaker's tiredness is a current, changeable state.

Why is hoje placed at the end of the sentence?

Adverbs of time like hoje are commonly positioned at the end of a sentence in Portuguese to indicate when an action occurred. Placing hoje at the end emphasizes that the studying, which is the reason for feeling tired, took place specifically today, following the natural flow of the sentence.