Question

英语的过去式,现在进行时,改肯定句,否定句等等,都怎么改!

Answer 1

例：write为原形 一般现在时：He writes his paper.
肯定句：He wrote his paper.（把动词原形变为过去式即可）
He is writing his paper.[把动词原形变为be(注意人称am,is,are）+v.-ing]
改为：
否定句：He didn't write his paper.(可以理解为把过去式“转移”到助动词上变为didn't,动词则变回原形）
He isn't writing his paper.(可以理解为直接be动词后加not,即为否定形式）
一般疑问句：
Did he write his paper?(用助动词过去式did提问,放句首,其它顺序不变,但动词变为原形）
Is he writing his paper?(直接提前原肯定句be动词形式,其它顺序不变）
特殊疑问句：（提问"paper")
What did he do?（特殊疑问词+did+原句顺序）
What is he doing?（特殊疑问词+原肯定句be动词形式+原句顺序