A plural noun indicates that there is more than one of that noun (while a singular noun indicates that there is just one of the noun). ... Regular plurals follow this rule (and other similar rules), but irregular plurals are, well, not regular and don't follow a “standard” rule.
I believe that the adverb phrase is "during the fifteenth century"
You will play football again like a champion
<span>These are the lines that best describe the irony
in this excerpt.</span>
Within four years organize and run an event to raise money for charity within four years earn a certification in personal finance