问题补充：
You’ll find taxis waiting at the bus station you can hire to reach your host family.
A. which
B. where
C. when
D. as
答案：
(答案→)A. which
B. where
C. when
D. as
解析： 考察定语从句的引导词：which是关系代词，指物，在句中作主语和宾语。本句句意：你会找到一辆等在车站的出租车，搭载你到寄宿家庭。从句中缺少宾语，which充当hire的宾语，修饰先行词taxis。Where，when，都是关系副词，不充当成分。As 不能充当宾语。本题选A.
