---Mum, I’m leaving for Beijing tomorrow morning.
--- Oh, good. But be sure to phone me you get to Beijing, please.
A. because
B. why
C. when
D. if
网友回答
A. because
B. why
(答案→)C. when
D. if
解析:连词辨析。Because因为;why为什么; when当……时; if是否,如果。句意:妈妈,我明天上午要动身去北京了。——哦,太好了。但是当你到达北京时一定要给我打电话。结合语境可知选C。