Question

What is the subordinate clause in the following sentence?: He opened the door after hearing the doorbell ring.

Answer 1

No.

Explanation:

Sorry, here has no subordinate any clause as this is a simple sentence and only one clause made the complete sense that is a sentence too.

after hearing the doorbell ring ==is a prepositional phrase only.

Or He opened the door when he heard the doorbell ring.

Here "when part" is a subordinate clause.