(a) Tom is a carpenter; Malta is an island; Gold is metal; The dog is in the garden; The roads were rough and narrow; Peter was tall and fair. (b) I am hot; I am cold; He was excited; He was calm; They will be happy; They will be unhappy. Tom is being foolish; Tom is foolish. The children are being quiet; The children are quiet. You are being stupid (= «You are not trying to understand»); He is being difficult (= «He is raising unnecessary objections»); He is being funny (= «He is only joking. Don’t believe him»); She is just being polite (= «She is only pretending to admire your car/clothes/house etc.»). (c) How old are you? – I’m ten / I am ten years old. (NO: I’m ten years); How old is the tower? – It is 400 years old. (d) How tall are you? / What is your height? – I am 1·65 metres; How high are we now? – We’re about 20,000 feet; What is your weight? / What do you weigh? / How much do you weigh? – I am 65 kilos / I weigh 65 kilos. (e) How much is this melon? / What does this melon cost? – It’s L1. The best seats are (=cost) L25
[Las formas son las mismas de «be» usado como auxiliar. (a) be es el verbo que se usa para significar la existencia de, o para dar información acerca de, una persona o cosa; (b) be se usa para expresar condición física o mental. Con ciertos adjetivos, e.g. «quiet«/»noisy«, «good«/»bad«, «wise«/»foolish,» es posible usar la forma continua de be, e.g. «Tom is being foolish,» para significar que el sujeto está mostrando esta cualidad en este momento. «Tom is being foolish» significa que Tom está hablando o actuando neciamente ahora, en este momento; «Tom is foolish» significa que Tom siempre habla o actúa neciamente. «The children are being quiet» significa que están jugando tranquilamente ahora, en este momento; «The children are quiet» significa que siempre juegan tranquilamente. Otros adjetivos incluyen: annoying, cautious/rash, clever/stupid, difficult, economical/extravagant, formal, funny, generous/mean, helpful/unhelpful, irritating, mysterious, optimistic/pessimistic, polite, selfish/unselfish; Con algunos de estos adjetivos, e.g. «stupid,» «difficult,» «funny,» «polite,» la forma continua implica que el sujeto está actuando deliberadamente de esa manera (You are being stupid = «You are not trying to understand»). (c) be se emplea para la edad, («years old» debe usarse cuando se da la edad de cosas). (d) Tamaño y peso se expresan mediante be. (e) be se emplea para precios.]
A Practical English Grammar (A.J. Thomson & A.V. Martinet) 