Why comma after therefore and unluckily but not after sometimes

English as a Second Language English Vocabulary, Grammar and Idioms
1

Hi teachers,

  1. Sometimes, therefore, unluckily etc are adverbs. We use a comma after “unluckily, therefore” but not after “sometimes”. Why is it so?

  2. I would like to travel any date from 19th to 25th of October. Please correct it.

Many thanks.

2
  1. Do you have examples of what you mean? This does not seem to be a general rule so context is required.

I would like to travel on any date from 19th to 25th October.

3

Thank you very much.

Unluckily, I missed the bus.
Sometimes I drive to work.
He didn’t study. Therefore, he failed the exam.

4

This comma usage is context dependent, not word dependent. It has nothing to do with what word it follow, but depends on the general structure, meaning and emphasis of each sentence.

Unluckily, I missed the bus.
The comma is used here because ‘unluckily’ is additional to the main phrase ‘I missed the bus’. It contains extra information (about how you feel about missing the bus) but is not part of the speaker’s main point.
In another context the comma might not be used (at least, not in the same place).
I ran for the bus, but unluckily I missed it.

Sometimes I drive to work.
The main point here is that you drive to work on occasions. ‘Sometimes’ is an important part of the statement.
Here’s an example where there’s be a comma after the word ‘sometimes’:
Usually, I walk, but sometimes, if I’m feeling lazy, I drive to work.

He didn’t study. Therefore, he failed the exam.
is incorrectly punctuated.
This is correct
He didn’t study, therefore he failed the exam.

5

I am confused.
According to Understanding and Using English Grammar by Betty S. Azar:
Al didn’t study. Therefore, he failed the test.
According to your explanation, it is punctuated incorrectly. Why is it so? Is it an old-fashioned?

6

For me, these are both acceptable:

“Al didn’t study. Therefore, he failed the test.”
“Al didn’t study. Therefore he failed the test.”

I note, though, that Beeesneees thinks at least the first is wrong.

7

Thank you very much.
Al didn’t study, therefore he failed the test. Is it also acceptable?

8

I personally do not like that very much. For me, the comma seems too weak before “therefore”. However, opinions about this obviously vary.