不定式、分词、动名词作定语时的比较 现在分词、过去分词、动名词 可以作前置定语，而不定式不能作前置定语。 如：① a developing country , a developed country ; boiling water，boiled water ; ②building materials , a swimming pool ; the sleeping boy , the coming new year 。 辨异的方法很简单：① 现在分词具有主动、进行的特点，而过去分词则具有被动、完成的特点。例如： a developing country=a country which is developing (进展中国家 )； boiling water=water which is boiling(正在滚开的水 ) ; a developed country=a country which has developed（发达国家 ）； boiled water=water which has been boiled(已滚开过的水)。② 现在分词和动名词同形，但作前置定语时，动名词表示所修饰的名词的用途， 例如：building materials = materials for building; a swimming pool = a pool for swimming ；而现在分词作前置定语时，表示所修饰的名词正在进行的动作，两者是逻辑上的主谓关系。 例如：the sleeping boy=the boy who is sleeping ; the coming new year=the new year that is coming 。B．作后置定语 不定式、现在分词、过去分词都能作作后置定语，而动名词不作后置定语。先看例句： ① The problem to be discussed at the meeting is very important.② The problem discussed discussed at the meeting is very important.③ The problem being discussed at the meeting is very important. 辨析比较：上面例句分别用不定式、现在分词、过去分词作后置定语，是因为它们存在不同的情况：不定式作定语，表示动作正要进行（未发生）；现在分词作定语，表示动作正在进行（正在发生）；过去分词作定语，表示动作已完成（已发生）。据此，我们可以把上面的例句还原为定语从句作定语的句子，这样学生就更容易理解：①The problem to be discussed at the meeting is very important. = The problem ( which is ) to be discussed at the meeting is very important.②The problem discussed at the meeting is very important. = The problem (which was ) discussed at the meeting is very important.③The problem being discussed at the meeting is very important. = The problem (which is ) being discussed at the meeting is very Important.动名词的复合结构有四种形式： ① 形容词性物主代词＋动名词； ② 名词's＋动名词； ③ 代词宾格＋动名词；
