Ut each word in brackets into suitable word or verb forms: It would Ответ (had better) if you had finished it yesterday.

To put each word in brackets into suitable word or verb forms, the sentence will be:

"Было бы лучше, если ты закончил(а) это вчера."

In this sentence, the word "had better" is expressed as "лучше" in Russian. The verb "had finished" is adjusted to the past tense, singular second person, and has gender variation to include both masculine and feminine forms — "закончил(а)".