The warmth of ( ) sweater will of course be determined by the sort of ( ) wool used.A:the;the B:the;\ C:\;the D:\;\为什么?

The warmth of ( ) sweater will of course be determined by the sort of ( ) wool used.A:the;the B:the;\ C:\;the D:\;\为什么?
The warmth of ( ) sweater will of course be determined by the sort of ( ) wool used.
A:the;the B:the;\ C:\;the D:\;\
为什么?

The warmth of ( ) sweater will of course be determined by the sort of ( ) wool used.A:the;the B:the;\ C:\;the D:\;\为什么?
选择B
第一个空 表示类别 the /a 都可以,
第二个空 sort of / kind of 后加名词 ,通常不加任何冠词
或者还可以理解为 wool 羊毛 为物质名词 非特指的物质名词前不加任何冠词（物质名词为构成其他东西的材料的名词）

因为他是以这件sweater作为特例来阐述一个事实，所以加the
the sort of wool used用的那种羊毛已经说了是the sort of，后面就不用加the了