I am not going to leave this room. If you wanted to expand this sentence to include the following clause, "until you apologize t
o me," which would be the most effective expansion of this sentence? A) I am not going to leave this room until you apologize to me. B) Until you apologize I am not going to leave this room to me. C) I am not going until you apologize to me to leave this room. D) I am not, until you apologize to me, going to leave this room.
If the underlined phrase is <em>having been warned by her mother, </em>then this is a nonessential perfect participial phrase. Nonessential phrases are separated from the rest of the sentence by commas, and since this is a perfect participle, this is the only correct option.
