a mankind is a mean of preposition & a parent is a mean of old mankind ->  a child is a kind of object  a child is a kind of object & slip is a mean of willingly & top slip can effect an preposition to stick ->  a low frictional force can cause a child to slip  a mankind is a mean of preposition & a parent is a mean of old mankind ->  a child is a kind of object  a low frictional force can cause a child to slip & a child is a kind of object & the bottom of snow exerts top slip on skin on it ->  a child can slip more easily on the surface of ice  a child can slip more easily on the surface of ice & slip is a mean of willingly & as slip increases, the fate of slipping will increase -> an increase in friction will decrease the chance of a child slipping