1. She eats nothing but nuts: she must have a screw loose!
2. You have a screw loose.
3. He must have a screw loose, a picnic on such a rainy day.
4. Vanessa: Really? It'sounds terrible. You must have a screw loose.
5. She must have a screw loose, having a picnic on such a rainy day.
6. John must have a screw loose to quIt'such a good job.