为什么这个英语的句子缺少谓语
Thediscususedintrackcompetition,oncedesignedwithitsweightconcentratedinametalcenter,butnowlinedwithleadaroundtheperimeter,therebyimprovingstabilityinflightandresultinginlongerthrows.
谓语不是use吗?然后designed修饰前面的
答案是这个句子缺少谓语