请教一道题

definition:"A family is a household containing a hoseholder and at least one person related to the householder."Except for the homeless and people in group living quarters,most people live in households.

According to the definition above,which of the following must be true?

A)All families include a householder

B)Some people residing in group living quarters are members of families.

1)请问这是一道假设题还是结论题?

2)答案是A,为什么B不对?

刚开始准备,问题有点低级,谢谢指教

是结论题，注意题干中的must be true。

A family is a household containing a hoseholder所以A)All families include a householder正确。

B)Some people residing in group living quarters are members of families.不一定。比方说，这些some people都未成家，所以没有family。

奇怪的问题一个：

A family is a household containing a hoseholder

中household containing a hoseholder是指：一个有户主的家庭,而不是其他家庭

还是指：一个家庭，而有一个户主是所有家庭的特征。

其实也就是关于限定与非限定的问题