many people have been ill from a strange disease these days,_____we have never heard of before .

题目

many people have been ill from a strange disease these days,_____we have never heard of before .
it
that
one
this

答案

one
这四个指示代词的区别是：
it指代上文提到的同名同物的东西；
that指代与上文同名但不同物的东西；
one表示泛指,表示上文所提到的一个人或物；
this用于指代下文将提到的东西.
题中disease前面有a,说明是泛指.因此正确答案是one.one表示a disease.
不明白的可以再问哟!