动名词是动词的一种非谓语形式。动名词的构成和现在分词相同。

动名词具有名词的特点：可在句中作主语、宾语和标语。动名词也具有动词的某些特点：要求宾语和带有状语，这是就构成了动名词短语。动名词也有主动和被动、一般和完成等形式。以DESIGN为例：主动态

被动态

般式 Designing Being designed

完成式 Having designed Having being designed

动名词和动名词短语的用法

动名词及短语在句中可作主语、宾语和表语。例如：（1） Heating the water changes it into vapor. 把水加热可以使水变为蒸汽。（Heating the water在句中作主语，water是heating的宾语。）

（2）Closing the switch connects the cranking motor to the battery. 合上开关就把启动马达与蓄电池接通了。（句中closing the switch作主语，switch为closing的宾语。）

（3）Oxygen does not burn, but does support burning. 氧布自燃，但能助燃。（burning是动名词，作support的宾语。）

（4）Energy is involved in doing work, or in heating on object. 能量在于它能做功，或使物体变热。（动名词doing和heating均为介词in的宾语。）

（5）In the dynamo, mechanical energy is used for rolating the armature between the poles of an electromagnet. 在直流发电机中，机械能被用来转动电磁铁两极之间的电枢。（动名词rotating是介词for的宾语。）

（6）One way to fit the pieces of a broken iron bar together is heating the iron until it softens and pounding it with a hammer. 把一根断成数截的铁棍连接起来的一个方法就是把铁加热至软化，然后用铁锤去锻打。（句中heating和pounding均为表语。）

动名词的被动态

当动名词的逻辑主体是动名词的动作对象时，该动名词通常用被动形式。例如：

（1）When a vapor condenses, the energy that it absorbed in being baporized is again released as heat. 当蒸汽冷凝时，它汽化时所吸收的能量又以热的形式释放出来。（it用来代替vapor，it时vaporize这一动作的承受者，所以要用动名词的被动形式being vaporized.）

（2）It is assumed that every substance which is capable of being magnetized consists of a very large number of molecular magnets….人们假定，能够被磁化的各种物质都是由大量的分子磁体组成的….（句中which用来代替substance，which时动词magnetize这一动作的对象，所以magnetize的动名词应用被动形式。）