又是一道GWD！！. GWD26-Q20

茉莉蔷薇

In 1981 children in the United States
spent an averageof slightly less than two and a half hours a week doinghousehold chores; by 1997 they had spent nearly six hours a week.
D

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

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

C.chores, whereas nearly six hours a week werespent 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

D错在拿chores和figure of 6 hours在比肯定是不对了？

by+time 的意思是 not later than，截止1997年的意思，所以应该用过去完成时。
个人感觉，这个by 和grow 呼应的很好，把一个过程个清楚的描述出来了，呵呵

A指代不清，they 可以指代chores，但是不是有规则说，同位置的代词指代相同的名词么？两个都是主语啊

In 1981 children in the United States
spent an averageof slightly less than two and a half hours a week doinghousehold chores; by 1997 that figure had grown to nearlysix hours a week

云游

我觉得A是时态问题：
In 1980 children did...; by 1997, children had done...
A中需要对比两个时代children所花时间的不同，用完成时表达不出对比的含义。
最好就是用过去时；in 1997, children spent nearly 6 hours a week.