Follow the 'Grammatical Notes' for a more detailed explanation. Juan . . . Con esa actitud . Ahora . . . . . Esos alumnos . . .
Te aseguro que . . . . .
Seguramente . . . Top Not a valid choice. Improper use of positive-negative elements in a normal negative context. Proper use of positive-negative elements in a normal positive context. A positive context pertains if no 'negative element' appears before the verbal nucleus.