Which sentence is correct?

No comma is needed.

Hi. Your examples are the pattern of so called Relative Clause.

denna1001I'm telling mom that you stole her keys.

It's correct and called Defining Relative Clause. That cannot be ommited there. In the Defining Relative Clause, Subordinate Sentence cannot be put out because the meaning of the whole sentence will be unclear or distorted.

Hi Goodman. Do my statements sound reasonable?

FandorinYour examples are the pattern of so called Relative Clause.

Sorry. No. Verbs of telling take noun clauses as objects. that is a complementizer, not a relative pronoun, and the that-clause is a complement of the verb, not an adjectival construction (which is what relative clauses are).

She said (that) the keys were stolen

Hi, Jim. Thank for replying. I guess I've caugh that. Adjective Clause and Noun Clauses are Subordinate Clauses, aren't they?

Thanks everyone.

CJ already explained.

In the original sentence, "that" did not relate to "I am telling mom". So it doesn't have a "relative" property.

CJ 's examle is very clear. The keys that were stolen were the keys to the front door. (Relative (adjectival) clause)

denna1001I'm telling mom, you stole her keys.

I'm telling mom that you stole her keys.

you would choose this one because you wouldent just say i,m telling mum that you stole her keys.

May be I get the wrong end of the stick. So, what you're saying is that Noun Clause is not a Subordinate Clause. I'm confused w

FandorinAdjective Clause and Noun Clauses are Subordinate Clauses, aren't they?

Yes!