The error in this sentence is a A) pronoun-antecedent voice agreement error. But it should be noted that this has become more standard usage in common dialogue.
Just be focus and never give up on what you want to achieve. If you want to have a high school diploma but all your focus on it and you will come out successful
The present perfect refers to an act that took place in the past, from the perspective of the present. "I have eaten" means that at some point in the past, eating occurred. Now (at the present), it is over.
The simple present tells you about what's going on currently. "I eat" means that the act of eating is ongoing. (Though it can also refer to a habitual act; I may not be eating right at this instant, but it's the sort of thing that I could be doing right now, because the eating isn't complete.)
Ponyboy and Johnny had to disguise themselves because Johnny killed someone to save Ponyboy's life and they were on the run from the cops. Ponyboy loved his hair because it symbolized who he was and he was a Greaser.
