问题
选择题
Kids are not allowed to leave kindergartens their parents come to pick them up.
A．since
B．unless
C．although
D．because
答案
答案：B
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。