“as long as your arm”别理解成“和你的胳膊一样长”，真实含义是（清单）很长。

【例句】
The phone's been buzzing non-stop. I've a list of messages as long as my arm.
手机一直在不停地嗡嗡作响。我有一个很长的信息列表。

There's a list of repairs as long as your arm. Something just doesn't work.
我有一份很长的修理单。一些东西坏了！