The co-options of new members brought fresh perspectives to the committee.

The two concepts are co-extensive.

The co-tidal lines on the map show areas of equal tidal range.

The two events co-occurs frequently.

The two events are co-occurring.

The two events co-occurred last night.

During World War II, the United States and the Soviet Union were co-belligerents against Nazi Germany.

The co-belligerents fought together against a common enemy.

The co-original idea was presented by both authors.

There are many co-dependences in their relationship.