... are repeated, the series is divided by commas. The comma stands for, in effect, the word and . The comma before the final item, before and , is often optional, but it is used here to make clear ... shorter constructions appear early, and after a comma; longer one's appear at the end. Tactics and Strategies Some basic tactics and strategies for reading and writing should be apparent. ... the United States shall have the power to lay and collect taxes, duties, imposts and excises, to pay the debts and provide for the common defense and general welfare. In the final version a...