HI
E-GMAT,
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. 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
B. spent slightly less than an average of two and a half hours a week doing household chores; by 1997 that figure had grown to nearly six hours a week
C. had spent slightly less than two and a half hours, on an average, per week doing household chores, whereas nearly six hours a week were spent in 1997
D. spent an average of slightly less than two and a half hours a week doing household chores, compared with a figure of nearly six hours a week in 1997
E. spent an average of slightly less than two and a half hours a week doing household chores, that figure growing to nearly six hours a week in 1997
my queries is , Once the time frame is mention in the choices by In 1981 and By 1997 , then why we required past perfect tense? Could you please help me where I'm getting wrong .
Secondly , In choice B , could you please explain how the second clause is a Independent clause ,which started with "by 1997" construction ?.
Finally ,Choice C Isn't it the "compared with a figure" is a correct modifier?
Thanks