Peter’s parents were worried that Peter too much time on line.

The little elephant is afraid to go alone. He always walks _______ his mother. [ ]

Lee Min-ho is actor from South Korea. He sang Chinese pop song on the2014 CCTV New Year’s Gala.

Air quality in our city is becoming worse and worse. – Yes. These days’ PM2.5 readings are frightening. We must do something to _______ air pollution.

Look! Many people __________the buses at the bus stop.