Jennifer can sleep anywhere but Amy needs a good matress as 
OPTIONS:
- Jennifer has no back problems.
- Amy has no back problems.
Jennifer has no back problems.

To fix a wheel you need to have a good wrench handy.  The 
OPTIONS:
- wheel needs to be clamped.
- wrench needs to be clamped.
wheel needs to be clamped.

The teeth of Erin were a lot dirtier than Betty's teeth, due to 
OPTIONS:
- Erin being hygienic.
- Betty being hygienic.
Betty being hygienic.