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