I seem to always think of it AFTER the hand is over...

Pretty clear he's either on the FD or he's got an A. I'm not sure which, I'm about 50/50 either way. Should I check turn?

PokerStars No-Limit Hold'em, $0.50 BB (5 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

BB ($20.30)
UTG ($46.60)
MP ($29.95)
Button ($47.75)
Hero ($93.20)

Preflop: Hero is SB with 6, 7.
2 folds, Button calls $0.50, Hero completes, BB checks.

Flop: ($1.50) 3, 4, 5 (3 players)
Hero bets $1, BB calls $1, Button folds.

Turn: ($3.50) 2 (2 players)
Hero bets $3, BB calls $3.

River: ($9.50) T (2 players)
Hero bets $9, BB folds.

Final Pot: $18.50