Use comma in the following situations.
a) In lists
- I study physics, chemistry and mathematics.
- I went to Australia, New Zealand and France.
- He was tall, dark and handsome.
b) After linking expressions like however, nevertheless, on the other hand, moreover, in addition to, firstly, secondly, therefore, on the whole, to a great extent, even so etc.
- To conclude, I believe that English should be the primary foreign language taught in schools.
- However, this cannot be a solution to our problem.
- Arranged marriages are unusual in the West; on the other hand, they are very common in the Middle East.
c) After a subordinate clause
The comma can also be used to separate an adverb clause from the main clause. Adverb clauses usually begin with the conjunctions before, after, when, while, as, since, because, though, although, if, whether, unless, till and until.
Clauses beginning with these words are usually separated from the main clause with a comma especially when they come at the beginning.
- After he finished his studies, he went abroad. (Here we separated the adverb clause from the other clause with a comma)
- He went abroad after he finished his studies. (No commas are used here)
- Although I was not feeling well, I enjoyed the party.
When the adverb clause goes after the main clause, we do not normally use a comma to separate it.
- He was upset because he had failed the test. (We don’t use a comma here because the adverb clause goes after the main clause.)
Note that commas are not used to separate noun clauses because they are used as subjects or objects. They usually begin with ‘that’
- He said that he would come. (NOT He said, that he would come; here the noun-clause ‘that he would come’ is the object of the verb ‘said’)
d) In co-ordinate clauses
Clauses connected with and, but or or are usually separated by commas.
- God made the country, and man made the town.
- She lives on a small salary, but she will never take anything that does not belong to her.