Comments of Memento

I have watched the film Memento for twice, today I watched it again and finally I made a good comprehension of the film's narrative structure. It's complicated and a bit difficult to understand, I was greatly confused about the story when the first time I watched it.

This film was directed by Christopher Nolan in 2000. It talked about a detective named Leonard who is unable to make short-memory due to attacking by two men, during the attack, his wife was killed by them and Leonard's head was crashed into mirror and bleeding seriously.

The story was generally developed from a telephone, Leonard was talking to somebody else on the bed, when talked about something happened, the shot was flashback to a coloured picture, after finished displaying what happened then backed to the black & white picture that Leonard talking on the phone. The story was reversed the timeline and told from the end to the beginning, the result was that Teddy was killed by Leonard by pistol. The beginning was that Teddy told Leonard something about his wife that shocked him, it was his wife still alive and Leonard shot the injection for her everyday, but he remember these were happened to another person who was also unable to make short-memory as him. But Teddy finished talking, Leonard didn't kill him, the beginning cannot match the resolution that confused me a lot. Maybe this is the feature of this film that suspended and rethinkable. 

Below the words, the papers were written as the things happened in this film, it helped me a lot that I can get when is flashback or the reality.

And a question that I still confused that is about the word Teddy told to Leonard at the last of the film, if Leonard shot the injection for his wife everyday as Teddy said, the film maybe all performed in flashforward, because Sammy's appearance was treated as Leonard's inference and imagination; if the words Teddy told Leonard was not true or he was lying, maybe all the film developed in flashback.