In this chapter, dynamical systems possessing two quadratic vector fields with a single-linear-bivariate function will be discussed. Two inflection flows exist in such quadratic systems for appearing bifurcations of up- and down-parabola flows. The parabola source and sink infinite-equilibriums are for the switching bifurcations of parabola and inflection flows. The inflection source and sink infinite-equilibriums are for the switching bifurcations of two parabola flows in two directions. The inflection upper and lower-saddle infinite-equilibriums are for the switching bifurcations between two inflection flows in two directions. The corresponding parabola-flow arrays exist in such quadratic systems.