Some cities have passed laws that allow coal and oil ____ only i

Some cities have passed laws that allow coal and oil ____ only if their sulfur content is low.
A、burning
B、to burn
C、being burned
D、to be burned
【正确答案】：D
【题目解析】：本题考查的是allow sth. to be done，主动形式是allow sb. to do sth. ，此处是允许人们在硫含量低的情况下燃烧煤和石油，所以它们是被燃烧，用被动形式。