SECOND ROUND LEADERBOARD
Poulter and Rose topped the leaderboard before a late bogey
-14 Slocum/Weekley (USA)
-13 Montgomerie/Warren (Sco), Poulter/Rose (Eng)
-12 Goosen/Immelman (Rsa)
-12 Hansen A/Hansen S Denmark (Den), Cejka/Kaymer Germany (Ger),
Molinari E/Molinari F (Ita)
-6 Hoey/Maybin (Irl)
-5 Dodd/Dredge (Wal)
US duo Boo Weekley and Heath Slocum put in another strong display to stay a single shot ahead of England and Scotland on day two of the World Cup.
England's Justin Rose and Ian Poulter moved top of the leaderboard after the Americans bogeyed the fourth in China.
But birdies on the seventh, ninth and 11th put the US back on target.
England had enjoyed a faultless run on the front nine, with four birdies, and added another on the 10th, but a bogey on the 17th saw them drop back.
"It would have been nice to be bogey-free but that's out of the way now," said Poulter.
"We can certainly go into [Saturday] feeling good and certainly Sunday feeling happy with how we gelled and hitting tee shots like we did."
Montgomerie and Warren, meanwhile, did enough to ensure their two bogeys didn't hurt Scotland too much.
After picking up their first birdie on the fourth they bogeyed the short par-three fifth but birdies on the seventh and ninth ensured they kept in touch at the top at the turn.
They immediately bogeyed the 10th but added shots on the 555-yard 15th and the 18th to secure a second round score of four-under-par 68.
After starting the day alongside Scotland and England at nine under, Wales pair Bradley Dredge and Stephen Dodd - the 2005 winners - endured a disappointing second round.
Three consecutive bogeys from the first meant they were faced an uphill struggle and they also bogeyed the sixth to reach the turn at four over.
Bogeys on the 12th and 13th were cancelled out by an eagle on the tricky 15th before a birdie was added a hole later - but it was not enough to prevent Wales from dropping into a tie for 19th, nine behind.
Ireland's Michael Hoey and Gareth Maybin are tied for 15th after carding a level-par 72.