When talking about events that are not certain, European Portuguese offers several common expressions to convey probability or uncertainty. These expressions do not all behave the same grammatically, which is precisely where learners often get confused.

In this article, we will look at six frequent expressions used to express uncertainty and examine which verb forms they require: the subjunctive, the indicative, or the infinitive.

Expressions That Trigger the Subjunctive

In Portuguese, situations involving doubt, uncertainty, or subjectivity often call for the subjunctive mood. Three of the expressions discussed here follow this pattern.

The first is talvez. This adverb is almost always followed by the subjunctive, even though it appears directly before the verb, without any conjunction.

• Talvez vá ao mercado hoje à tarde.
• Maybe I will go to the market this afternoon.

Here, the verb ir appears in the present subjunctive (vá).

The same logic applies to é possível and é provável. In both cases, the verb in the subordinate clause is introduced by que and appears in the subjunctive.

• É possível que vá ao mercado hoje à tarde.
• It is possible that I will go to the market this afternoon.
• É provável que vá ao mercado hoje à tarde.
• It is likely that I will go to the market this afternoon.

The presence of que before the verb is a strong signal that the subjunctive is required.

An Expression That Uses the Indicative

Not all expressions of uncertainty trigger the subjunctive. A common exception is se calhar, which is widely used in informal European Portuguese.

With se calhar, the verb stays in the indicative, not the subjunctive.

• Se calhar vou ao mercado hoje à tarde.
• Maybe I will go to the market this afternoon.

Although the meaning still expresses uncertainty, grammatically this structure behaves like a straightforward statement.

Expressions Followed by the Infinitive

Some expressions of probability do not require a finite verb in the subjunctive or indicative. Instead, they are followed directly by an infinitive.

One such expression is ser capaz. This structure requires the preposition de before the infinitive.

• Sou capaz de ir ao mercado hoje à tarde.
• I might go to the market this afternoon.

The structure is fixed: ser capaz de + infinitive. Using any other verb form here would be incorrect.

Another very common verb that expresses likelihood or expectation is dever.

When used with this meaning, dever is followed directly by an infinitive, without que and without the subjunctive.

• Devo ir ao mercado hoje à tarde.
• I will probably go to the market this afternoon.

In this context, dever does not express obligation. Instead, it signals a reasonable assumption or expectation about what is likely to happen. This usage is extremely frequent in European Portuguese and is often closer in meaning to “probably” or “is expected to” than to “must”.

Key Takeaways

European Portuguese offers several ways to express probability and uncertainty, but each expression follows its own grammatical pattern.

Talvez, é possível and é provável trigger the subjunctive, often introduced by ‘que’. Se calhar expresses uncertainty while keeping the verb in the indicative. Ser capaz is followed by ‘de’ plus the infinitive, and dever, when used to express likelihood rather than obligation, is also followed by an infinitive (without ‘de’).

Understanding these differences is relevant, especially at intermediate levels where control of mood becomes increasingly important.

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Talvez vá a Évora

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Talvez vá à praia

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