Mom, this is my teacher, Miss Lin. Miss Lin, ____A. thank you. B. how are you? C. this is my mom.
-- Is tiffs your ruler? -- No, _________.A. this is B. it isn’t C. it’s not
Look! The traffic is moving fast. It’s _____ dangerous ____ cross the street now.
Everyone except Tom and John ___ there when the meeting began.
---How is everything, Masha? ----____.
We should do ____ to stop sandstorms(沙尘暴)from happening again and again.