Delta v is positive in this direction here, the work is negative. So work on the system is positive. Work done by the system is negative.

功是负的，总而言之,外界对系统做功的符号为正。

麻省理工公开课 - 热力学与动力学课程节选

And if delta G is greater than zero, then it goes spontaneously in the other direction.

如果dG大于零会怎样，那体系会向着反方向自发转变。

麻省理工公开课 - 热力学与动力学课程节选