问题
单项选择题
I was halfway back to the hospital where the doctor was working______Susan caught up with me．
A．when
B．while
C．until
D．though
答案
参考答案：A
解析： 考查状语从句辨析。本句考查时间状语从句，while后接延续性动词，而catch up with为瞬间动词，所以排除while。