didn’t see
see意为“看见”，其过去式为saw，否定形式为didn’t see
例句：
I saw a film last night．（改为否定句）
I didn't see a film last night
原句是一般过去时的陈述句，句子中有实意动词的过去式 saw，变否定句用助动词did，其后加not即可，did not可缩写为didn't，放于主语后，动词原形前，saw还原为see，其余部分顺序不变
①、动词是行为动词时，一般过去时的否定式是在动词原形前加助动词did not/didn't.
句型为：主语+didn't+动词原形
I saw him yesterday. 我昨天看见他了。
否定句：I didn't see him yesterday. 我昨天没有看见他了。
②、动词是Be动词时，一般过去时的否定式为be动词后面加否定词not。
句型为：主语+was not/wasn't， were not/weren't……
He was in Shanghai yesterday. 他昨天在上海。
否定句：He wasn't in Shanghai yesterday. 他昨天不在上海。
