Policymakers are happy to have the economy show any signs of life , be they bright green or sludgy brown .
政策制定者乐于见到经济的生命迹象，而不管其是很环保还是污染严重。
Most oil sands production currently involves digging up oily sand deposits near the surface and processing the sludgy material with heat and chemicals to free the oil and reduce its viscosity so it can flow through a pipeline .
