The girl saw a snake ____ on the road and was frightened.
----- It’s smoggy these days. That’s terrible!----- Yes, I hope to plant trees.________ trees, ______air pollution.
Thanks to the 2014 Winter Olympics, Sochi is well-known,_______?
---- ____________?---- Sorry, we’ll go and play in the park.
The safety of food has become one of the _________ problems in our daily life.
We are supposed to ___________a solution to stop people from looking down at their mobile phones while driving cars.