$0.10/$0.25 No Limit Hold'em Cash, 5 Players
BTN: $6.12 (24.5 bb)
SB: $35.07 (140.3 bb)
Hero (BB): $30.79 (123.2 bb)
MP: $25.42 (101.7 bb)
CO: $45.91 (183.6 bb)
Preflop: Hero is BB with Q♠ A♠
MP folds, CO raises to $0.75, 2 folds, Hero calls $0.50
Flop: ($1.60) T♠ 2♥ A♥ (2 players)
Hero checks, CO bets $1.06, Hero calls $1.06
Turn: ($3.72) K♦ (2 players)
Hero checks, CO checks
River: ($3.72) 8♦ (2 players)
Hero bets $2.79, CO raises to $6.25, Hero ?
Villian is 21/14 for 3.5k hands
Co open 23% ; Fold to 3-bet 62%
What hands can he check behind turn and then raise this river for value? 
I bet the river because I never expected him to raise me there, It just doesnt make any sense to me when he checks the turn with so many draws on the board. 
