肯定句:主语+动词过去式+其他
例如:I went to the park yesterday. i was happy yesterday.
否定句:主语+didn't +行为动词原形+其他
主语+was/ were+ not+其他
例如:i didn't come back yesteday.
I wasn't at home last night.
一般疑问句:Did +主语+行为动词原形+其他
Was/ Were +主语+其他
现在完成时用法
1.表示过去发生或已经完成的某一动作对现在造成的影响或结果。常用的时间状语:already,so far,never,just,before,recently,
I have lost my key.(说明过去某时丢的,现在还未找到。)
2.表示过去已经开始,持续到现在的动作或状态往往和表示一段时间的状语连用。for+一段时间,since+一段时间 How long..?
I ha...