They arrived London the morning of July 1.A. in inB. in onC. on inD. at on

问题补充：

They arrived London the morning of July 1.

A. in , in

B. in , on

C. on , in

D. at , on

答案：

A. in , in

(答案→)B. in , on

C. on , in

D. at , on

解析：到达大地点用介词in，在时间前只要有天的用介词on，本题中有个1号，故本题选B。