Como Se and the Imperfect

When you use como se, you are stepping into the realm of the unreal. Because the situation is hypothetical, Portuguese requires the Imperfect Subjunctive. You cannot use the regular present or past tense here. It is like a grammar law. If you say someone talks "as if they are rich," but they are actually broke, you need that subjunctive mood. It signals to the listener: "Hey, what I am saying right now is just a comparison, not a fact."

1. 1To build these sentences, follow these three simple steps:
2. 2Start with your main action in the present or past (e.g., Ele gasta dinheiro).
3. 3Add the connector como se.
4. 4Use the Imperfect Subjunctive of your second verb.
5. 5To find the Imperfect Subjunctive stem, look at the 3rd person plural of the Preterite (the eles form). Drop the -ram and add these endings:
6. 6eu: -sse
7. 7você/ele/ela: -sse
8. 8nós: -ssemos (don't forget the accent on the vowel before!)
9. 9vocês/eles/elas: -ssem
10. 10Example: falaram becomes falasse. comeram becomes comesse. foram becomes fosse.

You will use this pattern more often than you think. Use it when someone is pretending to be something they are not. Use it for vivid descriptions in storytelling. It is perfect for expressing sarcasm or skepticism.

• Real-world scenario (Job Interview): You might describe a candidate by saying, "He spoke as if he owned the company." (Ele falou como se fosse o dono da empresa).
• Real-world scenario (Ordering Food): "The waiter looked at me as if I were crazy for asking for ketchup on pizza." (O garçom me olhou como se eu fosse louco).
• Real-world scenario (Asking Directions): "She explained the path as if I lived here for years." (Ela explicou o caminho como se eu morasse aqui há anos).

Do not use como se for simple, factual comparisons. If you want to say "He runs like a professional," and he actually is one, just use como.

• Correct: Ele corre como um profissional. (Fact)
• Correct: Ele corre como se fosse um profissional. (Hypothetical—maybe he's just a fast amateur).

Also, avoid the Present Subjunctive. Even if you are talking about the present moment, como se almost always demands the Imperfect Subjunctive. It is just how the Portuguese brain categorizes these "as if" scenarios. It is like a grammar traffic light that is always stuck on the same color.

The biggest trap is using the Indicative (regular) tense. You might want to say como se ele é. Stop right there! It must be como se ele fosse.

Another common slip-up is forgetting the accent in the nós form. It is fôssemos, not fossemos. Yes, even native speakers mess this up in text messages sometimes. But you are a B2 superstar, so you will get it right.

Finally, don't mix up your stems. If the Preterite is irregular, the Subjunctive will be too. Ter becomes tivesse, not tesse. If you use the wrong stem, you might sound like a toddler trying to explain quantum physics.

Compare como se with parece que (it seems that).

• Parece que ele está doente. (It seems he is sick—this might be true).
• Ele age como se estivesse doente. (He acts as if he were sick—he is probably faking it for a day off).

Como se is much more skeptical. It highlights the gap between reality and the comparison. Parece que is more neutral. Think of como se as the "side-eye" of Portuguese grammar.