Clifton BrownThe Ravens' defense took a beatdown on Monday night, with Detroit Lions running back David Montgomery delivering the knockout punch. Detroit had a 98-yard touchdown drive in the first half and a 96-yard touchdown drive in the second half. Here are five thoughts on a loss that showed the Ravens have plenty of work to do:The Ravens' defense is giving up backbreaking plays. It's difficult to win when your defense gives up a 98-yard touchdown drive in the first half and a 96-yard touchdown drive in the second half. The Ravens didn't lose their first two games like last season, but falling to 1-2 with the schedule they have is no picnic.