at the airport he telephoned his wife and bold her what he would do when he got home.A.

问题补充：

at the airport, he telephoned his wife and bold her what he would do when he got home.

A. Once arrived

B. As soon as he reached

C. When he got

D. Upon arriving

答案：

A. Once arrived

B. As soon as he reached

C. When he got

(答案→)D. Upon arriving

解析：选项A中连词once表示条件，意为“一旦”，不合题意。选项B中reached是及物动词，后直接接宾语，因题中已有介词at，故B不能入选。选项C中的get 后接介词应是to，而不是at。选项D中的upon是介词，可与名词或动名词连用，表示“一……就……”，可入选。