  We use phase space methods to investigate closed, flat, and open
Friedmann-Robertson-Walker cosmologies with a scalar potential given by the sum
of two exponential terms. The form of the potential is motivated by the
dimensional reduction of M-theory with non-trivial four-form flux on a
maximally symmetric internal space. To describe the asymptotic features of
run-away solutions we introduce the concept of a `quasi fixed point.' We give
the complete classification of solutions according to their late-time behavior
(accelerating, decelerating, crunch) and the number of periods of accelerated
expansion.
