单项选择题A 'stationary source' ______.A.refers to where one goes to buy writing paper.B.may mean either a plant or a smokestack, but not both.C.is in this instance a legal term whose meaning is being questioneD.D.refers to something not covered by the abovE.
单项选择题A synonym for 'equilibria' is ______.A.choices.B.conventions.C.problems.D.interactions.