Should i bet here or check it down? Why?

***** Hand History for Game 2333970949 *****
$200 NL Hold'em - Saturday, July 09, 02:18:42 EDT 2005
Table Table 55281 (6 max) (No DP) (Real Money)
Seat 2 is the button
Total number of players : 6
Seat 1: bigbadbennyb ( $303 )
Seat 2: Pennypacker_ ( $196.7 )
Seat 3: WHITEBLACK ( $424.31 )
Seat 4: EvilEcstasy_ ( $100 )
Seat 5: FTPickle ( $186.55 )
Seat 6: ish42tc ( $465.41 )
WHITEBLACK posts small blind [$1].
EvilEcstasy_ posts big blind [$2].
** Dealing down cards **
Dealt to EvilEcstasy_ [ Kd Kh ]
FTPickle folds.
bigbadbennyb folds.
Pennypacker_ folds.
WHITEBLACK calls [$1].
EvilEcstasy_ raises [$3].
WHITEBLACK calls [$3].
** Dealing Flop ** [ 8d, 4s, 5d ]
WHITEBLACK checks.
EvilEcstasy_ bets [$7].
WHITEBLACK calls [$7].
** Dealing Turn ** [ Jc ]
WHITEBLACK checks.
EvilEcstasy_ bets [$20].
WHITEBLACK calls [$20].
** Dealing River ** [ 7s ]
WHITEBLACK checks.
EvilEcstasy_ ???