四种时态及其练习(完整版).doc

.四种时态(一般现在时、一般过去时、一般将来时、现在进行时)1 一般现在时。主要描述经常会发生的动作、状态或不变的真理。（1）标志词：always, usually, often, sometimes, hardly, ever, never; every second / hour /day / year / Friday/ June;once a week, twice two weeks;（2） 结构组成：主语+be+名词（形容词） I am a student. He is tall.否定句：在be 后加not I am not a student. He is not tall.疑问句：be 动词提前到第一位。 Are you a student? Is he tall? Yes, I am. / No, I am not.Yes, he is. / No, he isnt.主语+动词+地点+时间