it was in the apartment completed last year ( ) they celebrated their tenth wedding anniversary
问题描述：
it was in the apartment completed last year ( ) they celebrated their tenth wedding anniversary
A which B that C when D where
答
选择B,completed last year 是个后置定语,修饰apartment,可以无视它,拿去这部分之后就能很容易看出这是一个强调句型,所以应该选that（固定句型）