Yeah
IN THIS SENTENCE FIND THE MISTAKE

There is no mistake (unless you don't like dogs). 'I found a dog' is perfectly correct if you are talking about something that you did in the past as in "I was passing a car and heard a noise, there, under the wheel arch, I found a dog.". An alternative 'I've found a dog' implies that you are actually in the process of finding a dog or that you have just found one a few minutes ago.
it is not a i it is a L
yeah
I really don't know why I'm wasting my time on this.