--Do you know when the Chinese custom from?
--It's hard to say. But its characteristics the Tang Period.
A. began ; prove
B. started ; show
C. is ; appear
D. dates ; suggest
网友回答
A. began ; prove
B. started ; show
C. is ; appear
(答案→)D. dates ; suggest
解析：本题关键是抓住答句中所提供的信息，“It's hard to say'’，这表明回答者并不很肯定。而prove证明，show表明，排除A，B。前一空date from意为“追溯至……”