--- ______ you find ______ways to work out this problem, Jim? --- Yes, I ______.

She is so helpful that she is always ready to help people in trouble. Which of the following is correctfor the underlined word in the sentence? 

— ______ do you usually do at weekends, Susan? — I usually help my parents do some housework.

— What do you think of physics?— I think it’s ______ of all subjects.

—John, ______ do you visit your grandparents?—Once a week.