Clue: Take an age to score a single (6-3)
Answer: TWENTY-ONE
Explanation: Definition: age

**TWENTY** ("score") + **ONE** ("single") 
 
*Don't like the definition in this clue, unless there are parts of the country where "come of age" and "take an age" are interchangeable, but I have never come across "take an age" to mean anything other than to "take a long time"?