Commas before Introductory clauses/phrases

[Incoan]

Hello, I would like to ask you if the grammar and punctuation below is correct. If i understand correctly, all the beginning parts that I've seperated by commas qualify as "introductory clauses/phrases", but I am not sure. Thanks!

-In the section on the topic of Grammar, you can check your answers.

-Here, is another tip for you.

-Here, is a list of all subjects you need to learn. (I was told you don't need a comma here, and that made me confused)

-For more specific details, you should refer to specialized literature.

-In UK, the cost of treatment is more than you can afford.

-Just because this technology is so popular, doesn't mean that we should use it.

 

[bwkcaj_ca]

Incoan:

Perhaps the first thing you should realize about the use of commas is
that they are often difficult to use correctly -- even for native speakers
of English.

You should also understand that the main purpose of commas in English is make the meaning of a sentence clearer. When we read a sentence, a comma tells us to stop for a moment and think about what we just read.
If the sentence is clear without it, a comma is unnecessary.

Look at the following sentence:

Although I don't have much money, I'm going to go shopping tomorrow.

You can see there are two ideas in this sentence:

i. I don't have much money.
ii I'm going to go shopping tomorrow.

The comma separates the two ideas. This makes it easier for the reader to undestand what the writer is trying to say.

Grammatically,
'I'm going to go shopping tomorrow' is called an independent clause.

This means it is a complete sentence and it makes sense without the rest of the sentence.

'Although I don't have much money' doesn't make sense without the
rest of the sentence even though it is a complete thought.

It is called a dependent clause.

Rule 1

Commas are used to separate dependent from independent clauses
in a sentence.

Look at this sentence:

I don't have much money, in fact I don't have any, but I'm going to go shopping tomorrow anyway.

Here the comma separates a part of the sentence 'in fact I don't have any,' from the rest. If we remove the part between the commas, the sentence still makes perfect sense.

Grammatically, 'in fact I don't have any' is called a parenthetical expression.

Rule 2

Commas are used to separate parenthetical expressions from the rest of the sentence.

There are many other ways to use commas in English but these are
two of the most important.

Now let's look at the sentences you posted:

1. In the section on the topic of Grammar, you can check your answers.

This is correct (see rule 1) but if you reverse the clauses

'You can check your answers in the section on the topic of Grammar'

the comma is no longer needed and the sentence seems more natural.

2/3. These sentences are clear without the comma, therefore the comma is not needed.

4. OK. See Rule 1

5. The comma is unnecessay. The sentence should begin In the U.K. . . .

6. This comma is not required. The sentence contains only one complete
thought.