【正确答案】：
THE CONTEXT CLUE USED IN THE SENTENCE IS RELEVANT DETAILS.ALTHOUGH THE AUTHOR DID NOT EXPLAIN WHAT CLOP WAS,YET THE KEY WORDS SUCH AS SMACKING HER LIPS,BRANCHES,RIPE FORM A FRAME OF REFERENCE FOR US,IMPLYING IT IS SOMETHING EATABLE WHICH CAN BE OBTAINED FROM TREES WHEN RIPE. 
【题目解析】：句子中使用的上下文线索是相关的细节。虽然作者没有解释clop是什么，但是像咂咂她的嘴唇，树枝，成熟等关键词为我们形成了一个参照框架，暗示它是成熟后可以从树上获得的可食用的东西。