考點(diǎn)二　their等物主代詞
　　1．物主代詞是常見的名詞限定詞, 其后既可接可數(shù)名詞的單復(fù)數(shù)(his pen, his pens)又可接不可數(shù)名詞(his time), 但不可與其他的限定詞同時出現(xiàn)(部分?jǐn)?shù)詞除外)， 例如：不能說no my car, my no car，但是可以說 My two red cars
　　2．英語中許多習(xí)慣用法在表示特指時都用物主代詞而不用the, 為的是更突出所屬關(guān)系，這在TOEFL中是一個�？嫉狞c(diǎn)
例如：Manufacutrers of consumer goods often change the styles of their products.
這里用their 而不用 the
　　例題:
　　(1)
　　A good exercise program helps teach people to avoid the habits that might shorten the lives.
　　應(yīng)改為: their
　　解釋: 定冠詞the指代不清, 用物主代詞their作名詞lives的限定語更符合英語習(xí)慣, 還可突出lives 與people之間的所屬關(guān)系
　　(2)
　　A liquid is similar to a gas because has molecules are not fixed to each other in any specific way.
　　應(yīng)改為: its
　　解釋: has是動詞, 不能修飾名詞, 且與從句的謂語沖突, 依句意改為物主代詞its作molecules的限定語
　　考點(diǎn)三 只接復(fù)數(shù)名詞的限定詞
　　a (large /small /great /considerable /remarkable) number of, a variety of, a set of, a few, 等表示數(shù)的固定詞組之后總是接復(fù)數(shù)名詞
　　例題:
　　(1)
　　In mathematical terms, modern algebra is set of objects with rules for connecting or relating those objects.
　　應(yīng)改為: is a set
　　解釋: a set of是固定詞組, 表示一套、一組, 后面接可數(shù)名詞的復(fù)數(shù), 與題中objects吻合
　　(2)
　　At birth, an infant exhibits a remarkable number of motor response.
　　應(yīng)改為: responses
　　解釋: 短語a number of 后面要求接可數(shù)名詞的復(fù)數(shù), number前可加某些形容詞如great, considerable, remarkable, small 等表示a lot of 或 a few
　　注意 “the number of” 和 “a number of”的區(qū)別
　　The number of boys in Class Five is 25. (五班男孩的數(shù)目是25，后面謂語動詞用單數(shù))
　　A small number of families are able to afford an apartment. (少數(shù)家庭能夠買得起一套住房, )