The site now is a park which will be open to the public at the end of this year.A. to be

问题补充：

The site now is a park, which will be open to the public at the end of this year.

A. to be built

B. being built

C. having been built

D. Built

答案：

A. to be built

(答案→)B. being built

C. having been built

D. Built

解析：考察分词做定语。本句中的now说明是正在进行的事情，名词the site与动词build之间构成被动关系，故使用现在分词在句中作定语。句意：正在被建设的这个工地是公园，这个公园将会在今年年底向公众开放。故B正确。