---Why was Mr. Smith suddenly fired by his boss?---Because he was found in the non-smoking

问题补充：

---Why was Mr. Smith suddenly fired by his boss?

---Because he was found in the non-smoking office.

A. smoking

B. smoke

C. to smoke

D. smoked

答案：

(答案→)A. smoking

B. smoke

C. to smoke

D. smoked

解析：考查宾语补足语。Find sb doing sth发现某人正在做某事；find sb do sth发现某人做某事的全过程。本题句意：—为什么斯密斯先生被老板解雇？—因为他被发现在无烟办公室里抽烟。这里指他抽的时候当场被抓住。故A正确。