Breakdown of Hayvan bir hareketsiz duruyor, bir aniden atılıyor.
durmak
to stop, to stand
hayvan
animal
aniden
suddenly
bir
one moment ... the next (alternating)
Questions & Answers about Hayvan bir hareketsiz duruyor, bir aniden atılıyor.
How does the bir ... bir ... structure work in this sentence?
This is a correlative conjunction used to describe alternating actions. Instead of meaning the number "one", the pattern bir [action 1], bir [action 2] translates to "one moment [action 1], the next moment [action 2]". Here, it elegantly contrasts standing still with pouncing.
The verb atılıyor comes from atmak (to throw). Why does it mean "pounces" here?
You are right that atmak means "to throw". The -ıl- suffix is often the passive marker, but it can also make a verb reflexive (meaning the subject does the action to itself). So, atılıyor literally means "it throws itself," which is the natural Turkish way to say an animal "lunges" or "pounces".
In the phrase hareketsiz duruyor, is hareketsiz an adjective or an adverb?
It functions as an adverb here, telling us exactly how the animal is standing. In Turkish, many words can act as either adjectives or adverbs without changing their form. Hareket (motion) plus the suffix -siz (without) translates to "motionlessly" or "motionless" in this context.
Why are both verbs in the present continuous tense (duruyor, atılıyor)?
The bir ... bir ... structure requires both verbs to match in tense and person to balance the alternating actions. Using the -iyor tense for both shows that these contrasting actions are vividly happening right now as the speaker watches.