  Generally speaking, there is a negative kinetic energy term in the Lagrangian
of the Einstein-Hilbert action of general relativity; On the other hand, the
negative kinetic energy term can be vanished by designating a special
coordinate system. For general spherically symmetric metric, the question that
seeking special coordinate system that satisfies the positive kinetic energy
coordinate condition is referred to solving a linear first-order partial
differential equation. And then, we present a metric corresponding to the
Reissner-Nordstrom solution that satisfies the positive kinetic energy
coordinate condition. Finally, we discuss simply the case of the Tolman metric.
