In order to build a road,the old houses ___ used to stand in front of our classroom.,请问是选B吗?但为什么不选 A呢?In order to build a road,the old houses ___ used to stand in front of our classroom building have already been pulled down.A

In order to build a road,the old houses ___ used to stand in front of our classroom.,请问是选B吗?但为什么不选 A呢?In order to build a road,the old houses ___ used to stand in front of our classroom building have already been pulled down.A
In order to build a road,the old houses ___ used to stand in front of our classroom.
,请问是选B吗?但为什么不选 A呢?
In order to build a road,the old houses ___ used to stand in front of our classroom building have already been pulled down.
A:where B:that C:who D:what

In order to build a road,the old houses ___ used to stand in front of our classroom.,请问是选B吗?但为什么不选 A呢?In order to build a road,the old houses ___ used to stand in front of our classroom building have already been pulled down.A
因为used 缺少主语 ___ used to stand in front of our classroom building,这里需要给从句选一个主语,所以肯定不是A,又因为是房子不能使C,所以只能从BD中选一个,而后边的话是做houses的同位语所以选B