15. 此洞深三米。 正：The hole is three metres deep. 误：The hole is three metre deep. 析：名词短语threemetres用作状语修饰形容词deep，数次后面表示度量的名词按习惯用复数形式。如： It is nearly 5000 years old. 但是，当数词+度量词+形容词组成一个合成词，放在里一个名词前作定语时，那个表示度量的名词习惯上用单数。如：a six-metre-deep-hole一个六米深的洞，aten-story-high-building一栋十层高的楼房。 16. 王宏和马国都是男老师。 正：Wang Hongand Ma Guo are men teachers. 误：Wang Hongand Ma Guo are man teachers. 析：man和woman 用作定语时，表示性别其单数形式修饰单数可数名词，复数形式修饰复数可数名词。如：a man doctor一位男医生，three men doctors三位男医生，a woman nurse一位女护士，three women nurses三位女护士。 17. 蚂蚁身体里有两个胃。 正：The ant hastwo stomachs in its body. 误：The ant hastwo stomaches in its body. 析： stomach虽然是以ch 结尾，但其复数形式不加es，而直接加s。而遵守名词变复数的规则的则要加es.如：branch—branches树枝, bench—benches长凳, watch—watches手表。 18. 我到那里用了一个半小时。 正：It took meone and a half hours to get there. 误：It took meone and a half hour to get there. 析：英语中多于一个，即使不够二，也要用复数。如：one and a half years一年半。
