By the end of this year a new library in our school.A would be completed B will have be

问题补充：

By the end of this year, a new library in our school.

A would be completed B will have been completed

C had been completed D was being completed

答案：

解析：考查时态。By与完成时连用，the end of this year是一个将来的时间，使用将来完成时。句意：到今年年底，一座新的图书馆在我们学校将已经被建立。