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.
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 选B，不是很明白。我选的C A：they精确指代children,错误 D：compared逻辑主语不一致 E：growing做伴随改变了句意 有人说C错是因为in 1997改变了句意，但是我觉得句子本身要表达的意思就是1981年和1997年情况的对比。请大家指正，谢谢。 | 
