—When did your uncle arrive China?—He got to Guangzhou the morning of the 16th of April.

问题补充：

—When did your uncle arrive China?

—He got to Guangzhou the morning of the 16th of April.

A. at; in

B. in; in

C. to; on

D. in; on

答案：

A. at; in

B. in; in

C. to; on

(答案→)D. in; on

解析：arrive in大地点 arrive at小地点 在具体的某一天的早上用介词on。

句意为 “--什么时间你叔叔到中国?--他到达广州在4月16日的早上.”