см. тж. понижать ; уменьшать
• The liquid film impairs the efficiency of the column.
• The grade of rock must be kept high to hold down the shipping cost per unit of phosphate.
• The internal voids detract from the engine's performance.
• Efficiency was depressed ( or reduced ) by increases in liquid viscosity.
• The presence of carbon depresses the melting point of iron.
• The presence of nickel lowers the critical temperatures.
• Air resistance would whittle away the speed of ...