袖手旁觀

put the hands in the sleeves and look on -- to have nothing to do with a thing； fold one's arms and look on； look on and do nothing； look on unconcerned

例句

1. Don't just sit by while the other children are all busy. 別的孩子都忙著，你不要閑著袖手旁觀。

2. They stood looking on while the man was robbed. 正當那個人被搶劫時，他們卻站在那兒袖手旁觀。