Kids are not allowed to leave kindergartens their parents e to pick them up.
A. since
B. unless
C. although
D. because
网友回答
A. since
(答案→)B. unless
C. although
D. because
解析：连词辨析. Since由于,自从……以来；unless除非，如果不；although虽然，尽管；because因为；句意：如果他们的父母不来接他们，孩子们是不允许离开幼儿园的。结合语境可知选B。