四、单数可数名词作主语时。例如: The box is in your room. 箱子在你的房间里。 What is that girl doing over there? 那女孩在那边干什么? 五、单个数字、算式或单个字母作主语时。例如: Three plus nine is twelve. 三加九等于十二。 "I" is an English letter. "I" 是个英语字母。 六、指示代词this, that等作主语时。例如: This is her red pen. 这是她的红钢笔。 七、代词one作主语时。例如: One of them is watching TV. 他们中的一个人正在看电视。 八、不定代词something, anything, nothing 等作主语时。例如: There's something wrong with the computer. 这台电脑坏了。 善问大王:第三人称单数的主语有这么多啊!这下我可全知道了!Thank you very much. Mr Huang! Mr Huang: That's all right. 善问大王:Goodbye! Mr Huang: Bye-bye!