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
answer:B
B中的时态用的不对阿，我自己选的是D，请指教！ | 
