keep off grass远离草地； 例如The policeman told the boys to keep off the grass. Don\'t walk across the lawn; keep off the grass. 不要通过草地，勿...
sign的常用短语 用作名词 (n.) a sign of the times； 用作动词 (v.) sign away (v.+adv.)； sign in (v.+adv.)； sign off (v.+adv.)； sign on (v.+adv.)...
