Visibility impairment in national parks, wilderness areas and urban areas also continues to be a problem.
Wilderness area are having trouble with visibility impairment.
National parks are renowned for near-perfect visibility.
A dog does a trick.
The wealth effect refers to the phenomenon where people become wealthier as their friends do.
The schools band is practicing on their instruments.
The men are not very strong.
A federal employee has no pension plan.
Four men working on a railway track