问题
选择题
It was early morning in London _____ Prime Minister Cameron arrived to give his speech.
A．where
B．when
C．before
D．that
答案
答案：B
题目分析:句意：当首相卡梅伦来进行演讲时，他到达的时间是伦敦的清晨。固定句型：it was +时间点+when 从句，意思是“当某事发生的时候是……”，故答案选B。