[Grammar] dependent clauses, subordinating conjuctions and relative pronouns

[atabitaraf]

I got this grammar point form 'SUMMIT 2A, Joan Saslow and Allen Ascher'
To make a dependent clause (with subordinating conjunctions or relative pronouns) into a complete sentence, attach it to an independent clause. Use a coma if the dependent clause comes first.

1. Although Isabel Carter has painted many portraits, she hasn't yet sold any.
2. Isabel Carter hasn't yet sold any paintings, although she has painted many portraits.

My questions are:
1. Is using comma necessary when the dependent clause is first?
2. Is using comma optional when the dependent clause comes the second?

 

[MikeNewYork]

I got this grammar point form 'SUMMIT 2A, Joan Saslow and Allen Ascher'
To make a dependent clause (with subordinating conjunctions or relative pronouns) into a complete sentence, attach it to an independent clause. Use a coma if the dependent clause comes first.

1. Although Isabel Carter has painted many portraits, she hasn't yet sold any.
2. Isabel Carter hasn't yet sold any paintings, although she has painted many portraits.

My questions are:
1. Is using comma is necessary when the dependent clause is first?
2. Is using comma is optional when the dependent clause comes the second?

1. Yes.
2. No, it isn't optional. It is used in some cases and not in others. In your second sentence, the comma is needed because "although" sets up a contrast between the two clauses.

See many of the standard comma uses here: https://owl.english.purdue.edu/owl/resource/607/02/