1.   Efficient recycling is the only acceptable solution for Earth and the only key to sustainable life elsewhere in space.

2.   Even if she were replaced, her example demonstrates that party identification is not the only key to a clean Justice Department.

3.   I had the only key.

4.   And the building manager holding the only keys had gone home for the night.

5.   And technology is not the only key to improving safety.

6.   A self-taught pianist, C major his only key, Shawn found enchantment in jazz and show tunes.

7.   But swing voters may not be the only key to the Ohio election.

8.   Never, by the way, think that choosing the right fly is the only key to successful fly fishing.

9.   Technology, of course, is not the only key to improving safety.