问题
选择题
On his way home yesterday , Tom was hit on the head_____he had time to realize what was happening .
A．since
B．before
C．when
D．until
答案
答案：B
考查时间状语从句。句意“昨天在回家的路上，汤姆还没意识到发生了什么事，就被击中了头部。”before“在......之前，还没来得及......”。故选B。