问题
选择题
---Could you let me know ________ yesterday ?
---Because the traffic was heavy .
A．why did you come late
B．why you came late
C．why do you come late
D．why you come late
答案
B
题目分析：考查宾语从句。句意 你能告诉我昨天你为什么迟到吗？因为交通阻塞。Know后面跟着由why引导的宾语从句，用正常语序故排除AC，时间状语是yesterday，故用一般过去时，所以选B 项。
