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.

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

The answer is B. At first glance, I thought the B was right. But later I found "had grown" doesn't make sense. So i chose D. in the original sentence, "in 1981" use "spent", but why "in 1997" uses "had grown"? I am lost.

Can sb. give me some directions?

应该是B。

写这句话的时间是1998年，这样by 1997就可以用had了。

Yes, actually, I think this question is the same as one I've seen in OG or daquan, and the answer would be B. But I just couldn't figure out "spent" and "had grown". I still feel a little bit confused.

Anyway, thanks a lot.