Grammar COMPOUNDS A Compound is a combination of two or more words. In English most Compounds are formed by nouns modified by other nouns. The defining/modifying word(s) may also be adjectives, prepositions, adverbs or verbs. Sometimes Compounds are written joined together (glass + ware = glassware, green + house = greenhouse), sometimes they are joined using a hyphen (Earthquake-engineering), sometimes they are two separate words (Earthquake engineering). Remember that, in such sequences, the most important word always comes last (safety boots are boots, not safety !). The words which come before it just define the main word in more detail. Only the last word of the group can be made plural (construction yards). The other words function as adjectives, so they are invariable. A Compound can be used to indicate: what someone does (earthquake engineer), what something is for (safety equipment), what the qualities of something are (worldwide), how something works (settling tank), when something happens (everyday life), where something is (earth surface), what something is made of (stone walls) and so on. The word sequence may be quite long. For example, a revolutionary new low-cost solar powered heating system is a heating system using the power from the sun and having a low cost , which is new and revolutionary . Compound adjectives are made up of a noun + an adjective (chemical-free), a noun + a participle (computer-aided), or an adjective + a participle (quick-thinking). It is important to use hyphens in some compound adjectives to avoid an ambiguous meaning. For example: rock-forming minerals are minerals that form rock , while rock forming minerals could refer to rock that forms minerals . Other combinations include: adjective + verb (double-check ricontrollare ), noun + verb (landmark pietra miliare ), preposition/adverb + verb (output emettere ), verb + preposition/adverb (check-in registrarsi ), verb + verb (water-proof impermeabilizzare ). 180 Module 5 BRICKS AND MORTAR