The most important thing to keep in mind when dealing with emergency is to stay calm.A. /

问题补充：

The most important thing to keep in mind when dealing with emergency is to stay calm.

A. /; the

B. the; an

C. the; the

D. /; an

答案：

A. /; the

B. the; an

C. the; the

(答案→)D. /; an

解析：答案：D。考查冠词。句意：一定要牢记处理紧急情况时一定要保持镇静。第一空keep in mind是固定短语，意为“牢记”；第二空an emergency“紧急情况”。