[Grammar] Since i have/i graduated?

[Nima1000]

1. I have worked hard as an engineer since i have graduated.

2. I have worked hard as an engineer since i graduated.

Could you possibly tell me is correct ?
Could you tell me what difference is in meaning?
Could you answer me simply because i am learning english.
thanks.

 

[Rover_KE]

You have already been told that I is always capitalised.

 

[emsr2d2]

You have also been told to capitalise the first letter of every sentence and to capitalise proper nouns.

 

[M1na]

Please pay attention to the comments above. And make changes towards the capitalisations and punctuations.
Besides, the first sentence is not correct. For perfect tenses, we use "since" + a point in the past. Therefore, when the point is completely unknown you cannot use since. The second sentence, however, can be correct. But it is better to mention the time exactly like in 1982 or etc.

 

[Nima1000]

Thank you.I am sorry for my misstakes.ok.

 

[Chicken Sandwich]

The second sentence, however, can be correct. But it is better to mention the time exactly like in 1982 or etc.

***** NOT A TEACHER *****

I don't see how that would be an improvement.

 

[5jj]

I don't see how that would be an improvement.

Quite! It wouldn't.