7. 用不定式作表语。如：
His goal is to be a doctor. 他的目标是当医生。
My duty is to protect my sisters. 我的职责是保护我的妹妹们。
My advice to you is to speak the truth. 我对你的忠告是讲真话。
My dream is to travel around the world. 我的梦想是环游世界。
8. 用动名词作表语。如：
Her hobby is growing roses. 她的爱好是种植玫瑰。
His job is looking after sheep. 他的任务是看羊。
My favorite sport is swimming. 我最喜欢的运动是游泳。
9. 用从句作表语。如(www.hxen.com)：
That’s what we are here for. 我们来这里就为了这个。
The question is how he did it. 问题是他是如何做此事的。
That’s where I first met her. 那就是我第一次遇见她的地方。
The trouble is that I have lost his address. 麻烦的是我把他的地址丢了。