why can you tell clocks are shy?

谜题：why can you tell clocks are shy?
 
（参考答案及解析在第二页）

谜底：because they always have their hands in front of their faces.
 
难度：★★★
 
谜语解析：略

上一篇：美籍华人（打一卫生巾品牌）
下一篇：伐木累（猜一英语单词）