Some pictures of the river brought the days back to the old they swam in it. A. whenB. th

问题补充：

Some pictures of the river brought the days back to the old they swam in it.

A. when

B. that

C. who

D. where

答案：

(答案→)A. when

B. that

C. who

D. where

解析：因为先行词是the days，并在定语从句中作状语。