大全secD-20

20.   The argument that the dominant form of family structure today is not the nuclear family, but rather it is a family which is modified and extended, is based on a number of facts: the existence of three-generational families, the amount of vertical and horizontal communication between family subunits, and the extent to which family members offer assistance to one another.

(A) family, but rather it is a family which is modified and extended, is based on a number of facts: the existence of three-generational families

(B) family, but is instead a family that is modified and extended, is based on a number of facts: three-generational families exist

(C) family, which has been modified and extended, is based on a number of facts: the existence of three-generational families

(D) family but a modified extended family is based on a number of facts: the existence of three-generational families（D）

(E) family, but also a modified and extended family, is based on a number of facts: three-generational families exist

这是不是考的not.... but....的句型 。可排除掉B,C,E,

A ，but rather 中it指代错误，the dominant form

是的。

The dominant form is not ...but ...

The argument is based on ...