  In a pristine monolayer graphene subjected to a constant electric field along
the layer, the Bloch oscillation of an electron is studied in a simple and
efficient way. By using the electronic dispersion relation, the formula of a
semi-classical velocity is derived analytically, and then many aspects of Bloch
oscillation, such as its frequency, amplitude, as well as the direction of the
oscillation, are investigated. It is interesting to find that the electric
field affects the component of motion, which is non-collinear with electric
field, and leads the particle to be accelerated or oscillated in another
component.
