Questions & Answers about Både versen och metaforen är vackra.
Why is the adjective vackra in the plural form here instead of matching the singular nouns?
Even though both versen and metaforen are singular en-words, the phrase både ... och ... (both ... and ...) links them into a plural compound subject. Because the subject is plural overall, the predicative adjective must take the plural form vackra.
How does this plural agreement work if we add an infinitive, like in the 'tough-movement' structures we are currently learning?
The agreement stays exactly the same! If you wanted to say 'Both the verse and the metaphor are beautiful to read', it would be Både versen och metaforen är vackra att läsa. The adjective vackra still agrees with the plural subject, and the infinitive phrase att läsa simply attaches to the end.
Does the phrase både ... och ... affect the V2 (verb-second) word order?
No, både versen och metaforen functions together as a single, unified noun phrase. Because this entire phrase sits in the subject position (the first block of information), the verb är correctly takes the second spot in the sentence. It behaves exactly as if you had just used a simple pronoun like de (they).
What if one of these nouns was an ett-word instead of an en-word? Would the adjective change?