Final answer:
The Book of Songs from China, a collection of 305 ancient poems, cannot be easily dated due to its composition over several centuries from about 1000 BC to 400 BC.
Step-by-step explanation:
The poetical book that cannot be easily dated is The Book of Songs from China, which is a collection of 305 poems composed over a long time period extending from about 1000 BC to 400 BC. Due to its extended period of composition and the fact that there isn't a precise chronology for each individual poem within it, The Book of Songs presents challenges in terms of precise dating. These poems were eventually written down and have become a treasure in the study of ancient Chinese literature and philosophy, contributing significantly to the culture and history of China.