The independent clause is 'When the doorbell rang.'
It is an adverbial clause, modifying the verb 'was sleeping'.
The independent clause in the sentence "Trevor was sleeping when the doorbell rang" is "Trevor was sleeping." This clause can stand alone as a complete thought, while the phrase "when the doorbell rang" serves as a dependent clause that provides additional context.
No, "the doorbell rang" is not an independent clause; it is an independent clause. An independent clause contains a subject and a predicate and expresses a complete thought. In this case, "the doorbell" is the subject, and "rang" is the predicate, making it a complete idea.
"You rang the doorbell" is an indepent clause, because it can exist on its own. So is "but no one answered," because it is using a coordinating conjunction, which acts as a independent marker for an independent sentence. See https://owl.english.purdue.edu/owl/resource/598/01/.
An independent clause stands alone.
An alternative term for a main clause is an independent clause.
Only an independent clause can stand independently. A dependent clause is dependent on an independent clause.
An independent clause is a sentence that can stand on its own.
A complex sentence is a sentence that contains an independent clause and at least one dependent clause. The independent clause can stand alone as a complete sentence, while the dependent clause relies on the independent clause to make sense.
A clause can not stand alone in a sentence, whereas an independent clause can stand alone in a sentence.
This question is somewhat ambiguously phrased, because independent and dependent clauses are mutually exclusive categories, and a clause that is introduced by a subordinate conjunction is not independent by definition. However, substituting a coordinating conjunction in a independent clause by a subordinate conjunction can convert an initially independent clause into a dependent clause.
It can be an independent clause or a dependent clause. It is an independent clause if does not have a word at the beginning like "but" or "because". If there is a word like this at the beginning of the clause, it is a dependent clause.
I think you can't have a subordinate independent clause. A subordinate clause is a clause which is dependant on another clause it can't stand alone as a sentence. An independent clause can stand alone as a sentence.