I think _______ our duty to keep our environment clean and tidy.
My father is a . A. work B. worker C. works
We in Canada. A. live B. living C. lives
The math problem is so hard. I really don’t know________.
We played badminton ______ Sunday afternoon.
–Have you ever ________ an amusement park?--Yes, I have.I ________ Fun Times Amusement Park last year.