Breakdown of Дети сейчас лезут на горку.
сейчас
now
на
on, at / by (transport) / to (a place) / to (in answer to)
дети
children
лезти
to climb / to crawl (unidirectional)
Questions & Answers about Дети сейчас лезут на горку.
Why do we use лезут here instead of лазят?
Лезут is the present tense of the unidirectional verb of motion лезть. Because the sentence specifically says they are climbing right now (сейчас) in a single, ongoing direction (up the slide), we use the unidirectional form. If the kids were climbing up and down repeatedly, or if climbing the slide was a general habit, you would use the multidirectional verb лазить (which conjugates to лазят).
Why does the sentence use на горку rather than the prepositional case?
Verbs of motion like лезти require the accusative case to show the destination or direction of the movement. We use the preposition на because the children are climbing onto the surface of the slide. Since горка is a feminine noun ending in -а, it changes to -у in the accusative case, becoming горку.
Is the infinitive of лезут just лезать?
No, the infinitive is лезть. It belongs to a group of verbs ending in -зть or -сть that look a bit unusual but are quite consistent once you know the stem. The present tense uses the stem лез- and adds standard Type 1 endings: я лезу, ты лезешь, and for "they", они лезут.
Does mean "mountain" here?