be brewing
if something unpleasant is brewing, it will happen soon
=Trouble is brewing/ There is trouble brewing
There is difficulty, danger, or unrest fermenting or expected to arise in the future
مشرف بودن، در شرف وقوع، در آستانه وقوع
در آستانه چیزی بودن
"to be at the point where something is about to happen"
For example: Mountain gorillas are on the verge of extinction.