When he is free, he often helps his parents ________ some housework.
It is said that the gravity on Mars is only about __________ of the gravity on earth.
While Helen _____ along the river after supper, she ____ a wallet lying on the roadside.A. was walking; was finding B. walked; foundB. walked; was finding D. was walking; found
I stopped the car ____ a short break as I was feeling tired.
______ the students were when they heard the rock music!
______ you keep trying till the end, you will never know how strong you are!