What kind of clause is as soon the doors opened?

"As soon as the doors opened" is a subordinate clause, specifically an adverbial clause of time.

Here's why:

* Subordinate clause: It cannot stand alone as a complete sentence and needs an independent clause to make sense.

* Adverbial clause: It modifies the verb in the main clause by indicating the time of the action.

* Time: The clause tells us when the action of the main clause happened (i.e., as soon as the doors opened).

Example:

* As soon as the doors opened, the crowd rushed in.

In this example, "as soon as the doors opened" modifies the verb "rushed" in the main clause, telling us when the crowd rushed in.