Each of the following sentence has one mistake, underline it and correct it.
1. They not go to school on Sundays.
=> do not
2. When I saw her, I thought she looked happily.
=> happy (look + adj)
3. She tells me what to get to the market.
=> how
4. He does not know how to take care for himself.
=> of (có cụm take care of: chăm sóc)
5. In this school, athletics are compulsory.
=> is (athletics là 1 môn, dù có "s" phía sau nhưng vẫn là số ít)