Food safety is important. Rules to stop people from food pollution.
It is polite ______ you to give seats to the elderly.
-Why are there a lot of dead fish in the river?-Because they were ______ by the polluted water.
- Thank you so much for the gift.-_______.
_______ points you get, _______ levels you’ll go to.
Boys, don’t stop-please _______ with your work.