Question

the fire destroyed which was in the building

The fire destroyed _ was in building.A,all B .ALL that C.that D.which

Answer 1

选B,all that 相当于what,做的是destroy的宾语.
句子中缺少的即使destroy的宾语,有事从句的主语,双层身份的时候是what,但是没有what,再次可以用all that.
希望可以帮到你.