我是英语专业的专科生，如果六级没过的话，那么专...

下列活动中属于最基本的实践形式的是（ ）

A.物质生产活动
B.处理社会关系活动
C.科学实验活动
D.艺术表演活动

甲状腺肿大的判定标准为（ ）。

A.可看到肿大又能触及，在胸锁乳突肌以内为Ⅱ度
B.不能看出肿大，但能触及为工度
C.可看到肿大，并伴有血管杂音为Ⅲ度
D.腺体肿大超过胸锁乳突肌外缘为Ⅲ度
E.可看到肿大，并触及结节为Ⅲ度

We first think of the traditional or nuclear family．This is a two-generation family,the father and the mother and their own children．Most couples wanted to have four children,two boys,two girls.
Some nuclear families,however,may add one or more grandparents to come to live with them,that is three generations．This kind of family with grandparents,parents,and grandchildren is called an extended family．This family type was not very common during the later half of the twentieth century,but it's becoming more common now as an elderly grandparent moves in to live with a son or daughter．This is more possible now that American homes have become larger．What is interesting,however,is that after the grandchildren move out of the home and start their own families,this extended family shrinks back to a nuclear family,with just two generations again living together,a grandparent and parents,with the grandchildren coming only for occasional visits．
Now,the fatherless or motherless family is one kind of what we call a single-parent family．In the fatherless family it's just the mother and her children．As I said,this can be the result of the husband's death,of an unmarried mother,of a separation or divorce．There are also a growing number of motherless families--where the father raises the children,for any of the same reasons．A motherless family may also be fatherless,but still a family with one adult．This is becoming more common in the big cities where a grandmother will raise her daughter's children while the daughter goes elsewhere to work.
One other new kind of family is becoming increasingly more common．A single parent with one or more children will marry again．Perhaps the other parent is also a single parent．Together they will start what is called a blended family,which blends together or combines the children from two other families.

Who usually looks after the children in a both motherless and fatherless family in America?

A.The children's aun
B.The children's nursery or schoo
C.The children's grandmothe
D.The children's neighbou