this is the best movie( ----) we have seen this year填which还是that呢,为什么啊

this is the best movie( ----) we have seen this year填which还是that呢,为什么啊
this is the best movie( ----) we have seen this year
填which还是that呢,为什么啊

this is the best movie( ----) we have seen this year填which还是that呢,为什么啊
用that
因为先行词前有最高级best,只能用that ,不能用which

the best ....后面加that 所以用 that

that 因为有了限定词the best只能选that，这是搭配问题。基本情况下是that和which都可以的，但是出现the ,someting anyting == 就一定要用that..