Read the sentences. The concert attendees roared their approval. The band played a new song. Which revision uses a subordinating conjunction to combine the two sentences?

Subordinate conjunctions are connectors or parts of speech that connect two clauses together, an independent clause and dependent clauses.

They are used based on the relation between the two clauses. Subordinate conjunctions are like when, as, although, because ...

In this sentence both subordinate conjunctions of time and cause are possible to use.

The concert attendees roared their approval because the band played a new song.

or

The concert attendees roared their approval when the band played a new song.