These challenges are particularly difficult for those pollutants that are not emitted directly but instead form through secondary processes.
The pollutants that are not emitted directly have a difficult challenge.
The pollutants that are not emitted directly have an easy task.
There are two dogs.
Girl is sitting next to a map
the man is inside
I don't know if they have to option to choose well.
A kid is by the beach.
Dunkan was nowhere to be found.