+495.+ The comma is the mark used to indicate a slight break in the
thought.
There are a number of rules given for the use of commas. These rules,
like the rules for the use of capitals, you cannot commit to memory;
but, after repeated practice in your own writing and paying attention to
your reading, you will gradually develop an instinctive sense of the use
of the comma. Select some book which you are reading and go through it,
noticing especially the use of the commas. See if you can determine the
reason which prompted the author to place his commas where he did.
Notice, also, what effect the placing or the omission of the comma would
have upon the meaning of the sentence.
+496.+ +The Comma indicates the slightest degree of separation between
the parts of a sentence.+
+RULE 1.+
+497.+ +Words, phrases and clauses, forming a series and used in the
same construction, should be separated from each other by commas when
the conjunctions are omitted.+