什么是 trough?A long, narrow, generally shallow receptacle for holding water or feed for animals.Any of various similar containers for domestic or industrial use, such as kneading or washing.A gutter under the eaves of a roof.A long, narrow depression, as between waves or ridges.A low point in a business cycle or on a statistical graph.Meteorology An elongated region of relatively low atmospheric pressure, often associated with a front.Physics A minimum point in a wave or an alternating signal.