A) No.
B) I would try to avoid using the word however at the end of a sentence, as it is usually used to introduce a clause which contradicts something which has already been said, or is a relative adverb - and ought to precede that to which it relates.
Yes, typically a comma is used before the word "however" when it is at the end of a sentence to indicate a pause. For example: "I wanted to go to the party, however, I had to study for my exam."
It really depends on the context but it's not uncommon for commas to be used.
Yes
A comma is typically placed before "or" when it separates independent clauses in a sentence. However, a comma is not needed after "or" in most cases.
When using the word "however" in the middle of a sentence, you use commas before and after the word if combining a independent and dependent clauses. You may also use it for two independent clauses or use a ";" before the word however followed by a comma.
A comma is not typically used before "therefore." However, a comma may be used after "therefore" to separate it from the rest of the sentence when it is starting the clause.
A comma is generally not needed before "because" in a sentence. However, if "because" is introducing a dependent clause, a comma can be used after it to separate it from the main clause.
In general, when "but" is used as a conjunction, a comma is not needed before it. However, if the phrase following "but" is an independent clause, then a comma is typically placed before "but."
Depending on what the sentence is about you may use a comma before 'called';however, in some instances you may not be allowed to place a comma before the word called.
When using the word "however" in the middle of a sentence, you use commas before and after the word if combining a independent and dependent clauses. You may also use it for two independent clauses or use a ";" before the word however followed by a comma.
Before
In general, when "but" is used as a conjunction, a comma is not needed before it. However, if the phrase following "but" is an independent clause, then a comma is typically placed before "but."
Say your sentence aloud. If you find you pause before the word 'therefore', you will probably want to insert a comma. If you do not pause, no comma is required. Use a comma when the sense requires it, not because you have a specific word in your sentence.
If the word 'however' is in the sentence, commas should be placed on both sides. Eg: Blahblahblah, however, blahblahblah. If,however, the word 'however' opens the sentence, the comma should only be placed after the word. Eg: However, blahblahblah.
Not necessarily. Commas are a feature of sentence structure. There is no word or phrase in English that requires a comma.
Yes, typically a comma is placed before the word "unless" when it is used to introduce a dependent clause in a sentence. This helps to clarify the relationship between the main clause and the conditional clause.
A comma is not typically used before "therefore." However, a comma may be used after "therefore" to separate it from the rest of the sentence when it is starting the clause.
The comma goes before the word "but." For example: I was going to spell the word "comma" right, but then I fell into a coma.
No you don't.
It depends on the sentence.