his arrival at the airport he was greeted by many teenagers holding flowers in their hand

问题补充：

his arrival at the airport he was greeted by many teenagers holding flowers in their hands．

A. Upon

B. Within

C. Through

D. Beyond

答案：

(答案→)A. Upon

B. Within

C. Through

D. Beyond

解析：Upon his arrival at the airport他一到飞机场就……。