Questions & Answers about Я не смогу прийти сегодня вечером.
What tense/aspect is не смогу, and why is it used to mean “won’t be able”?
Смочь is the perfective counterpart of мочь (to be able). Perfective verbs in Russian do not have a present tense, so я смогу (“I will be able”) is a simple future form. Adding не gives не смогу = “I will not be able.”
Why is прийти in the infinitive after смогу?
Modal verbs like мочь/смочь (can, be able) are followed by a second verb in the infinitive. Therefore смогу прийти literally means “I will be able to come.”
Why is прийти perfective, and could I use the imperfective приходить here?
Прийти is the perfective form, indicating a single, completed action (arriving once). The imperfective приходить describes repeated or ongoing actions. Since you’re talking about one arrival tonight, you use прийти. Saying не смогу приходить would imply habitual or continuous coming, which doesn’t fit a one‑time event.
What case is вечером, and how does сегодня вечером function in the sentence?