His travel guide is completely dog-eared from being used so often.

dog-eared 是由名词 dog（狗）和形容词 eared（有耳朵的）组成的复合形容词。ear 指"耳朵"，eared 表示"有耳朵的"。 dog-eared 字面意思是"像狗耳朵一样"，用来形容书页因为经常翻折而卷起的边角，引申为"书页翻旧卷边的"或"皱巴巴的"。