八大时态的结构表
一般现在时的结构：动词+原形。一般过去时的结构：含有Be动词主语+was/were+形容词或者名词；不带be：主语+didn't+动词原形+其他。现在进行时的结构：Be动词(am/is/are)+doing；否定结构：Be动词(am/is/are)+not+doing。
一般现在时
1.基本结构：动词+原形(如主语为第三人称单数，动词上要加(e)S)。
2.否定形式：am/is/are+not；此时态的谓语动词若为行为动词，则在其前加don't,如主语为第三人称单数，则用doesn't，同时还原行为动词。
3.一般疑问句：把be动词放于句首；用助动词do提问，如主语为第三人称单数，则用does，同时，还原行为动词。
4.例句：It seldom snows here.
一般过去时
1.基本结构：含有Be动词主语+was/were+形容词或者名词；不含有be动词：主语+动词过去式+其他。
2.否定句：带be:主语+was/were not+形容词或者名词+其他；不带be：主语+didn't+动词原形+其他。
3.一般疑问句：含be动词was或were放于句首；不含be动词用助动词do的过去式did提问，同时还原行为动词原型。
4.例句：She often came to help us in those days.
现在进行时
1.基本结构：Be动词(am/is/are)+doing.
2.否定形式：Be动词(am/is/are)+not+doing.
3.特殊疑问句：把be动词放于疑问词的后面。
4.例句：How are you feeling today？
过去进行时
1.基本结构：was/were+doing.
2.否定形式：was/were+not+doing.
3.一般疑问句：把was或were放于句首。
4.例句：At that time she was working in a PLA unit.
现在完成时
1.基本结构：have/has+done.
2.否定形式：have/has+not+done.
3.一般疑问句：have或has提前。
4.例句：I've written an article.
过去完成时
1.基本结构：had+done.
2.否定形式：had+not+done.
3.一般疑问句：had放于句首。
4.例句：As soon as we got to the station, the train had left.
一般将来时
1.基本结构：am/is/are+going to+do；will/shall+do.
2.否定形式：am/is/are+not+going to；will/shall+not(will适用于所有人称，shall只用于第一人称)。
3.一般疑问句：be放于句首；will/shall提到句首。
4.例句：They are going to have a competition with us in studies.
过去将来时
1.基本结构：was/were+going to+do；would/should+do.
2.否定形式：was/were+not+ going to+do；would/should+not+do.
3.一般疑问句：was或were放于句首；would/should提到句首。
4.例句：He said he would go to Beijing the next day.
