If carried out properly, AFRICOM's work can complement that of the State Department, USAID, and other U.S. Government agencies working on the continent and help contribute to lasting peace and stability across Africa.

CENTERFORSECURITYPOLICY: A stimulus for African security

Second, European leaders are working to lay out a path to financial union, which is a necessary complement to monetary union.

WHITEHOUSE: Press Briefing by Jay Carney and Ben Rhodes

First, European leaders are working to lay out a path to financial union, which is a necessary complement to monetary union.

WHITEHOUSE: Press Briefing

But the ISS partners have to make contingencies, and if Soyuz rockets are out of service for a while, the station will see its crew complement reduced - perhaps all the way to zero.

BBC: November deadline for ISS crews

Despite their reforms, the three sisters have stuck to the idea that chemicals and pharmaceuticals complement each other, because the cyclical fluctuations in the former are cancelled out by streams of cash flowing from the latter.

ECONOMIST: The chemicals business

The goals of maximizing profit and fulfilling a moral agenda conflict more often than they complement one another, and investors who want to put ethics first have turned out to be relatively few.

FORBES: Magazine Article