They are not allowed here.A. to smokingB. to smokeC. smokeD. smoked

问题补充：

They are not allowed here.

A. to smoking

B. to smoke

C. smoke

D. smoked

答案：

A. to smoking

(答案→)B. to smoke

C. smoke

D. smoked

解析：句意：他们不被允许在这儿吸烟。allow sb. to do sth.允许某人做某事，allow后跟不定式，故选B。