The two groups collaborated closely until 1872, when they broke away.

The two countries have been collaborating closely in the area of nuclear energy generation.

This year, however, the airlines and the government say they will collaborate closely.

If we do not at long last collaborate closely, the next crisis could be fatal for us.

The institute is a private foundation, but collaborates closely with the university.

Harry and I collaborated closely from 1939-43, discussing every step together.

But both collaborate closely and regularly with a specific composer.

They collaborate closely with each other on many projects.

The village maintains a police department that closely collaborates with its local school districts.

They collaborated closely until the poet's death in 2009.