SINGLE MINDED
Credit: NY Times Crossword - Aug. 5, 2012
Patrick Merrell

[The clues below can be answered by expressions which are very common, except for one thing: Each expression lacks the final S which is usually there. As the clues will indicate, the missing S is cleverly appropriate.]

1. Work to earn a C average.
2. Casually mention that you might know a secret
3. Still learning, but not completely inexperienced
4. Very small town's business directory
5. Future for one with limited retirement income
6. The First Amendment
7. Klutzy, but only occasionally
8. Beginning magician's repetoire
9. Go on a brief youthful binge
10. Disappointing response to, "Are you single?"

Answers:

1. Hit the book
2. Spill the bean
3. Wet behind the ear
4. Yellow page
5. Golden year
6. Bill of Right
7. Butterfinger
8. Bag of trick
9. Sow one's oat
10. Show of hand