би/б (у складеному присудку)

To use the conditional mood correctly, you must follow these rules for orthography, euphony, and placement:

1. The Writing Rule and Homophones:
The particle би/б is generally written as a separate word from the verb (e.g., читав би). It is fused in certain conjunctions, such as якби (if) and щоб (in order to). Crucially, do not confuse these with the separate forms що б (what would) and як би (how would), where the particle remains separate because що and як function as pronouns or adverbs rather than conjunctions.

2. The Phonological Rule (Euphony):
Ukrainian prioritizes melodic sound. Therefore, the choice between б and би depends on the word immediately preceding the particle, regardless of its part of speech:

• Use б if the preceding word ends in a vowel (e.g., вона б, я б).
• Use би if the preceding word ends in a consonant (e.g., він би, був би).

3. Placement and Enclitic Nature:
In a compound predicate, the particle naturally follows the finite auxiliary or copula (e.g., хотів би йти, був би вчителем). Following Wackernagel's Law, the particle often moves to the 'second position' in the sentence, right after the subject or an adverb. Importantly, the particle би/б can never be the first word in a sentence or clause; it must always follow a meaningful word.

4. Double Usage in 'If... then...' Sentences:
In hypothetical conditional sentences, the conditional marker must appear in both clauses. For example: Якби я знав, я б прийшов (If I had known, I would have come).

5. Morphology and Tense:
The conditional mood never uses present or future tense forms. It typically uses the past tense form of the verb, which does not conjugate by person but requires agreement in gender and number with the subject. Alternatively, it can use the infinitive (e.g., Піти б додому). When used with an infinitive, the structure expresses a strong wish, desire, or hypothetical suggestion (the optative mood), and the verb remains immutable.