and short of breath Andy and Ruby were the first to reach the top of Mount Tai .A. To be

问题补充：

and short of breath , Andy and Ruby were the first to reach the top of Mount Tai .

A. To be tired

B. Tired

C. Tiring

D. Being

答案：

A. To be tired

B. Tired

C. Tiring

D. Being

解析：

本句中的Tired and short of breath为形容词短语作状语，补充说明主语所处的状态。