《颜氏家训·省事篇》
古人说： 每件事都想做，又都做不好，那还不如专心干好一件事；土鼠有五种本领，却都难以派上用场。 
古人云： 多为少善，不如执一；鼷鼠五能，不成伎术。 
The ancients said: if you want to do everything, you will not do anything well. It is better to concentrate on doing one thing well; the field mouse has five abilities, but none of them can be applied.