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.

海报贴在墙上。
我在海报的背面贴了胶带。
cause

市中心的大楼倒塌了。
一场地震袭击了这个城市。
cause

我谢绝了生日聚会的邀请。
我不在城里。

cause