问题描述： keep up的中文 1个回答 分类：英语 2014-12-11 问题解答： 我来补答 *Bill had to word hard to keep up．比尔得努力才不落后.*The younger boys were not able to keep up in the race．年轻一些的小伙子们在赛跑中 展开全文阅读
