大全-16-9

9.     Studies show that young people with higher-than-average blood pressure and their families have a history of high blood pressure are more likely than others to develop a severe form of the condition.

(A) and their families have a history of high blood pressure

(B) whose families have a history of high blood pressure

(C) and a history of high blood pressure runs in the family

(D) whose families have a history of high blood pressure running in them（B）

(E) with a history of high blood pressure running in their family

I choose E or C. But the answer is B.

But B seems not parallel. Why?

Let me explain this myself.

9.     Studies show that young people with higher-than-average blood pressure and their families have a history of high blood pressure are more likely than others to develop a severe form of the condition.

(A) and their families have a history of high blood pressure
    [not parallel, and前面是n.后面是句子]

(B) whose families have a history of high blood pressure

(C) and a history of high blood pressure runs in the family [whose history?]

(D) whose families have a history of high blood pressure running in them（B）

(E) with a history of high blood pressure running in their family [whose history?]

Logical prediction + Parallelism

A and C 都是一样的错误, 即出现了第二个主谓   families have /runs

所以可以排除

E的话, 我觉得如果用了with就不需要再又running了

谢谢dingxiang! "A and C 都是一样的错误, 即出现了第二个主谓   families have /runs " - Good point!