GWD26-Q20

20. GWD26-Q20

In 1981 children in the United States spent an average
        of slightly less than two and a half hours a week doing
        household chores; by 1997 they had spent nearly six hours a week.
               E  b

A.      chores; by 1997 they had spent nearly six hours
        a week

B.      chores; by 1997 that figure had grown to nearly
        six hours a week

C.      chores, whereas nearly six hours a week were
        spent in 1997

D.      chores, compared with a figure of nearly six hours a week in 1997

E.       chores, that figure growing to nearly six hours a week in 1997

这道题目，答案选B，但是我觉得这个过去完成时态用的怪怪的

According to OG,

Past Perfect: this verb form is used with had to show the order of two events that took place in the past.

Example: correct:” by the time I left for school, the cake had been baked.”

这里并没有道理用过去完成时态的么

我选的是E 后面那个 that figure growing to nearly six hours a week in 1997  可以是主格结构吗～名词+ing

that figure growing to nearly six hours a week in 1997表达的意思是1997年才在增加。而不是到了1997年增加到...

另外，把后面部分改为同位语，首先不能用that figure,要用a figure that.(不会是独立主格，独立主格表达的是伴随)。

谢啦～可是对独立主格的用法还是不是很了解～CD上有什么关于这个的好的帖子么～