You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Czech_language

Context:
Typical of Slavic languages, Czech marks its verbs for one of two grammatical aspects: perfective and imperfective. Most verbs are part of inflected aspect pairs—for example, koupit (perfective) and kupovat (imperfective). Although the verbs' meaning is similar, in perfective verbs the action is completed and in imperfective verbs it is ongoing. This is distinct from past and present tense, and any Czech verb of either aspect can be conjugated into any of its three tenses. Aspect describes the state of the action at the time specified by the tense.

Question:
In which verbs in Czech is the action the verb describes still ongoing?

imperfective