Breakdown of Однако оптимизация заняла полтора месяца.
месяц
month
занять
to take (pfv)
полтора
one and a half [f. полторы, obl. полутора]
однако
however
Questions & Answers about Однако оптимизация заняла полтора месяца.
Why do we use полтора here instead of полторы?
The word for one and a half changes based on gender. We use полтора for masculine and neuter nouns, and полторы for feminine nouns. Since месяц (month) is masculine, полтора is correct.
Why is месяца in the genitive singular instead of plural?
In the nominative and accusative cases, the word полтора behaves just like the numbers 2, 3, and 4: it requires the following noun to be in the genitive singular. So, the nominative месяц becomes месяца.
Заняла is in the feminine form. Is it agreeing with оптимизация or the time expression?
It agrees with the subject of the sentence, оптимизация, which is a feminine noun. The time expression полтора месяца is the direct object here, acting as the answer to took how much time.
Why is the perfective verb заняла used here instead of the imperfective занимала?
We use the perfective занять to state the final, total amount of time a fully completed action took. If the process was still ongoing or if it happened repeatedly, we would use the imperfective занимать.