Pollution does great harm to our health. It’s necessary the environment.
I heard Lucy ________ happily in her room when I passed her house.
---Excuse me, I want to buy some food. Where can I find a supermarket? ---I know ________ not far from here. You can easily find ________.
Learning country’s language is a better way of knowing ________ culture behind it.
Beijing ______a lot in the past ten years. Now it has become one of the biggest modern______ in the world.
Sometimes playing computer games can ______ students’ study.