A (hormone estrogen) may prevent a (disease osteoporosis).Logical formLearned from8 sentences. A force may prevent workers from building a fence.Logical formLearned from8 sentences. A vested interest can be in preventing some flood of refugees.Logical formLearned from8 sentences. A shutdown may prevent payment of some contractors.Logical formLearned from8 sentences. A (cloud thermostat) may prevent (greenhouse warming).Logical formLearned from8 sentences. Vaccination may prevent viral infection.Logical formLearned from8 sentences. Preferences may prevent a male from appreciating a child.Logical formLearned from8 sentences. An existence may prevent a hardening of some axes.Logical formLearned from8 sentences. Means of preventing a disaster can be an effort.Logical formLearned from8 sentences. A fence may prevent a return to a (summer playground).Logical formLearned from8 sentences. A mechanism may prevent some (security holes).Logical formLearned from8 sentences. (Letter volume) may prevent replies.Logical formLearned from8 sentences. Persons may prevent an epidemic.Logical formLearned from8 sentences. Persons may prevent earthquakes.Logical formLearned from8 sentences. Discrimination may be prevented.Logical formLearned from8 sentences.