By using coupons at the grocery store, you could get twenty dollars' worth of groceries for only sixteen dollars.
a. written correctly
b. contains error in the use of apostrophes, hyphens, abbreviations, numbers, or numerals

henry fleming, crane's young hero, "had dreamed of battles all his
life" but learns to prefer "an existence of soft and eternal
peace".
a. sentence is written correctly
b. contains error in the use of dashes, parentheses, quotation
marks, or italics

most of the houses in the neighborhood were built at the turn of the
century. (not all of them are as nice as this one, however.)
a. sentence is written correctly
b. contains error in the use of dashes, parentheses, quotation
marks, or italics