I. 一词多义: 1. A mathematical or logical operation must meet a certain condition . 2. Interactive programming conditions are now available for some commercial programming languages. 3. The results of a biopsy (活组织检查) indicate a rare nonmalignant (非恶性的) condition . 4. The frequency with which the filter (过滤器) should be removed, inspected, and cleaned will be determined primarily by aircraft operating conditions . II. 词义的专义与多义 : 专义: concentration 1. The determination of trace concentrations of mercury in bio-logical materials is described. ( 化学 ) 2. A concentration process is important now that the depletion of high grade iron ores is a possibility. ( 冶金 ) 3. In spite of this, the relation between mineralogical composition of the ore, flotation reagent consumption and concentration results had been hardly touched upon in publications. ( 选矿 ) 多义: iron 1. An alloy containing carbon in excess of 2.11% in the iron -cementite diagram therefore is defined as a cast iron. (a chemical element) 2. Iron that is used in industry almost always contains carbon in a certain proportion. (a current name) 3. From the cupola, the iron flows into ladles of different sizes, and from these ladles it is poured into the models. (molten iron) 4. For separating iron from the impurities the iron ore must be melted. (containing iron) 5. Strike while the iron is hot. (a block of iron)