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I have a question about the following sentence:
The only artwork in evidence is/are some Greek vases and terracotta objects.
Is it "artwork" that selects the verb-form (therefore "is"), or "Greek vases and terracotta objects" ("are")?
I know the problem could be solved by saying "artworks", but in the context it's talking about a lack of artwork in the surroundings in general, i.e. wall frescoes, mosaics, carvings etc, so the uncountable "artwork" is more appropriate.