A.It means you must keep from the grass

B.It means you must keep off the grass

C.They mean you shouldn't keep off the grass

D.They mean you should keep from the grass

【答案】B

【解析】

句意：—那个标志是什么意思？—……。根据问句主语是第三人称单数，答语主语也用单数it它，keep off远离，keep away from远离，这意味着你必须远离草地。故选B。