Extensive efforts have been made to clean it up since the mid-20th century.

The confusing work of the democratic process will demand extensive effort in coming months.

It was the first extensive effort of any automobile division.

Extensive bipartisan efforts are continuing on the Act in 2011.

This time, we made extensive efforts to contact the victims' families for comments.

In addition, extensive efforts seek to eliminate Section 9 members at all costs.

Despite extensive efforts and publicity, there have been few, if any, strong leads.

Extensive efforts were made to control these fires before the expected heat wave at the start of January 2013.

Despite extensive efforts to boost the population, fewer than 100 exist there today, according to federal officials.

Extensive, wellmeant efforts had been made to keep the legal system up to date.