动名词作表语时，句子主语通常是表示无生命的事物的名词或what引导的名词性从句。表语动名词与主语通常是对等的关系，表示主语的内容，主语和表语可以互换位置。如果句中的主语和表语同为动词时，要注意保持两个动词在形式上的一致。以下是一些例句：

Your task is cleaning the windows.

*Your task is cleaning the windows.*（你的任务就是擦窗户。）

*Cleaning the windows is your task.*（擦窗户是你的任务。）

What I hate most is being laughed at.

*What I hate most is being laughed at.*（我最痛恨的就是被别人嘲笑。）

*Being laughed at is what I hate most.*（被别人嘲笑是我最痛恨的。）

The most popular pastime is playing chess.

*The most popular pastime is playing chess.*（最大众化的消遣是下棋。）

*Playing chess is the most popular pastime.*（下棋是最受欢迎消遣。）

The only thing that interests her is working.

*The only thing that interests her is working.*（她唯一感兴趣的事就是工作。）

*Working is the only thing that interests her.*（工作是唯一让她感兴趣的事。）

Our work is serving the people.

*Our work is serving the people.*（我们的工作就是为人民服务。）

*Serving the people is our work.*（为人民服务是我们的工作。）

What he likes is taking a walk after supper.

*What he likes is taking a walk after supper.*（他喜欢的是晚饭后散步。）

*Taking a walk after supper is what he likes.*（晚饭后散步是他喜欢的事。）

The story told by Mr. Wang is interesting.

*The story told by Mr. Wang is interesting.*（王老师讲的故事很有趣。）

*Telling the story is what Mr. Wang does.*（讲故事是王老师做的事。）

这些例句展示了动名词作表语时的用法和结构，强调了动名词与主语之间的对等关系，并且说明了主语和表语可以互换位置的特点。