A sinkhole usually forms by erosion caused by frequent exposure to water.

Hairdressers are thought to be at risk as well because of their frequent exposure to permanent hair dyes.

Even at sound levels below the level of possible damage, hearing protection will reduce fatigue from frequent exposure to sound.

Then there should be frequent exposure to music, as to any language, "to keep skills from getting rusty," he added.

Before the advent of a measles vaccine in 1963, virtually everyone could count on frequent exposure.

With frequent exposure to life on other worlds, he had acquired a different concept of what human living should be.

The frequent exposures soften him up and almost turn him into a nice guy.

Travelers to such areas may consider vaccination if they expect to experience frequent or prolonged exposure to tick habitat.

Indeed, we should be aware that frequent exposure to low doses of radiation can cause cancers and malformations.

Recent research in reading indicates that young children who have frequent daily exposure to "literacy events" at home are well equipped to become fluent readers.