Triples used as RDF terms:
https://www.w3.org/TR/rdf12-concepts/#section-triple-terms

Reifiying triples - also known as "occurences" have syntactic support in Turtle and wil have in JSON-LD and RDF/XML.
https://www.w3.org/TR/rdf12-turtle/#reifying-triples

Annotation support (syntactic support)
https://www.w3.org/TR/rdf12-turtle/#annotation-syntax

N-Triples does not have syntactic support
https://www.w3.org/TR/rdf12-n-triples/#triple-terms