。
She told us that the road was closed.
Literal
She [topic-は] us [to-に] that road [subject-が] is-closed [quotative-と] taught [for our benefit-てくれた].
An embedded clause acting as the content of 教える ('tell'). Inside the embedded clause, the subject takes が (not は) — その道路が — because は is reserved for the main clause's topic; embedded subjects default to が. The verb 閉鎖されている is the resultative passive ('is in a closed state'), built from 閉鎖する ('to close down') + passive ~される + ~ている for the resulting state. Wrapping the whole thing with と marks the embedded clause as the content being reported. The benefactive ~てくれる signals that the information was usefully shared with the speaker — turning a neutral 'told' into 'kindly let me know.'