这道题从句如果去掉后面的them就是一定语从句填上as 因为先行词被such修饰所以用as引导.意思是：这不是一部像广告上所说的那么好的电影.
但现在就你题上所说要填that也不对,不符合题意.所以还是要填as.
如 It is such an interesting book as we all want to read.
It is such an interesting book that we all want to read it.