一般现在时:He is my teacher.(陈述句) Is he your teacher?(一般疑问句) Yes,he is.(肯定回答) No,he isn't.(否定回答) 一般过去式: I watched TV last night. Did you watch TV last night? Yes,I did. No,I didn't. 现在进行时:My mother is cooking dinner. Is your mother cooking dinner? Yes,she is. No,she isn't. 一般将来时: I'm going to the bookstore this afternoon. Are you going to the bookstore this afternoon? Yes,I am. No,I'm not.