GRE Text Completion: PPO-GRE填空PPO - JT9L08827WOCQD12Q

Many of the unusual behaviors attributed to crows – such as drinking coffee or presenting gifts to people who feed them – are based on (i)____________ and therefore fall into the category of (ii)____________ rather than science. A. long-term observation B. anecdote C. controlled experiments D. speculation E. secondhand testimony F. hypothesis