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