In this task your given two statements in Chinese. You must judge whether the second sentence is the cause or effect of the first one. Label the instances as "cause" or "effect" based on your judgment. The sentences are separated by a newline character.

商店收银员叫保安。
顾客使用假币。
cause

那人刺穿了他的脚。
他踩在碎玻璃上。
cause

两个孩子同时伸手去取回球。
他们的头相撞了。

effect