Must and can: behar and -ke

Necessity is built by the verb behar + the main verb in the perfect form: Joan behar dut — I must go, literally "to go I-have-need". The object lives in the auxiliary, as wave 2 taught: Erosi behar ditut — I must buy them. For example: “Joan behar dut lanera orain” — I must go to work now. A rule from the Basque course: worked out on examples, not memorized as a wording.

Updated September 1, 2026 · Lingofly

How it works

Necessity is built by the verb behar + the main verb in the perfect form: Joan behar dut — I must go, literally "to go I-have-need". The object lives in the auxiliary, as wave 2 taught: Erosi behar ditut — I must buy them.

Possibility hides in the auxiliary too: -ke. Ireki dezaket? — may I open? Etor daiteke — he may come, a faceless "one can". The negation of possibility has its own word: Ezin dut etorri — I cannot come (wave 1 already said it this way).

The pair divides the work honestly: "behar" is about necessity, "-ke" is about permission and ability.

Table

Must and can: behar and -ke
mustcan / may
to gojoan behar dutjoan daiteke
to openireki behar dutireki dezaket
to buy themerosi behar dituterosi ditzaket

By example

  • Joan behar dut lanera orain
    I must go to work now
  • Ireki dezaket leihoa?
    May I open the window?
  • Ezin dut etorri gaur: lanpetuta nago
    I cannot come today: I am busy

How the rule settles in your head

A rule is not memorized from an explanation. It is memorized from an attempt to use it and a mistake — that is why the app delivers it mixed in with words, not as a separate lesson: it resurfaces exactly where you forgot it.

Frequently asked

Must and can: how does it work in Basque?

Necessity is built by the verb behar + the main verb in the perfect form: Joan behar dut — I must go, literally "to go I-have-need". The object lives in the auxiliary, as wave 2 taught: Erosi behar ditut — I must buy them.

What does it look like in an example sentence Basque?

“Joan behar dut lanera orain” — I must go to work now. A rule is easier to test on sentences like this than to memorize as a wording: what surfaces in conversation is the sentence.

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Test the rule on examplesPractice