That's it exactly.
I assume I have understood your question properly. Let's dig deep with the help of an example:
"He knows that a good time is on the way".
Sentence Structure:
He -> subject of the main clause.
Knows -> main verb of the main clause.
That a good time is on the way -> dependent clause, in which "a good time" -> subject, "is" -> linking verb, "on the way" -> prepositional phrase acting as an object of the verb "is" and modifying "time".
That -> expletive that introduces a sentence: "a good time is on the way."
Now let's go back to your question:
1- The word "that" is introducing a sentence.
2- Yes, this introductory word "that" can be treated as an expletive.
BUT be careful. In the below sentence that word "that" is used as a relative pronoun and can not be treated as an expletive. Rather, it is the subject of the dependent clause.
He knows the men that can kill the Governor.
No, an introductory word of a noun clause that is not part of the clause cannot be treated like a conjunction. Conjunctions are used to connect words, phrases, or clauses, while introductory words set the tone for the main clause but do not join clauses together.
Sure, I can use a conjunction like 'while' or 'although' to introduce an adverbial clause that provides additional information about an action or situation. Let me know if you would like me to demonstrate it with an example sentence.
No, "whoever" is a pronoun, not a conjunction. It is used to refer to any person or people without specifying who exactly.
The comma should be placed before a coordinating conjunction that links two independent clauses, after an introductory phrase or clause, in a series, and to set off nonessential information.
To separate an introductory phrase from the main clause, as in "After the meeting, we went out for lunch." To set off introductory words or adverbs at the beginning of a sentence, such as "However, I disagree with your assessment." To add clarity by signaling the beginning of the main idea or subject in a sentence, like in "In conclusion, we need to find a solution."
No, "recently" is an adverb, not a subordinating conjunction. Subordinating conjunctions are words like "because," "although," and "if" that join dependent clauses to an independent clause in a sentence. "Recently" does not perform this function.
A conjunction is a word that links two clauses to form a compound sentence. Each clause is like a sentence with a subject and a verb. Example: I like ice cream but I'm allergic to it. "I like ice cream" is a clause and can stand by itself. Same with "I'm allergic to it". The word "but" is a conjunction.
The adverb clause is "when the moon is full." The subordinating conjunction is when, the subject is moon, and the verb is "is."
what do these types of sentences look like : introductory phrase/clause , appositives and series conjunctions
Sure, I can use a conjunction like 'while' or 'although' to introduce an adverbial clause that provides additional information about an action or situation. Let me know if you would like me to demonstrate it with an example sentence.
No, "whoever" is a pronoun, not a conjunction. It is used to refer to any person or people without specifying who exactly.
The comma should be placed before a coordinating conjunction that links two independent clauses, after an introductory phrase or clause, in a series, and to set off nonessential information.
Nevertheless is tricky word to analyze. It is not an inference indicator, but is a subordinating conjunction. That means it used to join an independent clause with a dependent clause. The dependent clause is a statement whose meaning is incomplete without the driving clause. When writing a sentence with a subordinating conjunction there are two rules one must follow. If the sentence starts with the conjunction, the sentence requires a comma between the two clauses. If the sentence has the conjunction in the middle, then no comma is used (this is MUCH different from coordinating conjunctions like 'and,' but,' etc. Also, note that the dependent clause should not repeat the subject. John has homework to do nevertheless watches t.v. for 3 hours. Nevertheless watching t.v. for 3 hours, John has homework to do.
Everything not introduced by a co-ordinating conjunction (co-ordinators or coordinators) or a punctuation mark (i.e. a comma) is a subordinate clause (introduce by conjunctions like whereas, as because, or relative pronouns such as who, that, which, or relative adverbs like when, where, whenever, etc.
No, "recently" is an adverb, not a subordinating conjunction. Subordinating conjunctions are words like "because," "although," and "if" that join dependent clauses to an independent clause in a sentence. "Recently" does not perform this function.
The word like can be a verb, or a conjunction (meaning as, similar to), and more rarely a noun.It is arguably acting as a preposition in constructions such as "swims like a fish" (truncated clause like a fish swims).
A conjunction like "and" should typically come before a semicolon, following the first independent clause and before connecting it to the next independent clause.
Commas are not categorized into specific "types" like you mentioned. However, some common comma uses include separating items in a list, joining independent clauses in a compound sentence, setting off introductory phrases, and separating adjectives.