clean sheet有以下几种意思

(1) (在球赛或赛季中)无失球（英文解释 an instance of conceding no goals or points in a match or competition (esp in the phrase keep a clean sheet)

We're happy with the 1 - 0 win and and another clean sheet.  

我们对1-0的胜利,继续不失球感到满意.

(2)清白历史

Henry has apologized for his bad behaviour and should be allowed to rejoin the group with a clean sheet.  

亨利对他过去的不端行为表示歉意,如果今后不再重犯错误,应该被允许重新加入这个小组.

(3)空白纸

Take a clean sheet of paper and down the left-hand side make a list.  

拿张白纸，在左下方列个单子。

(4)干净床单

She ripped a clean sheet up to make bandages.  

他扯破一条乾净的床单,以做绷带.

She put a clean sheet on the bed.  

她把干净的床单铺在床上.

备注：clean sheet in 15 matches属于第1种意思, 是1个名词短语。