Today
Today is a nice day, it's sunny, isn't very hot, in the morning, the end of the last math class this semester, and the final exam, I must be ready to review.
Today is a nice day; it’s sunny, but it isn’t very hot, especially in the morning. With math class ending this semester and the final exam coming up I must be prepared to review. (As you can see I didn’t change too much just some minor adjustments.)
Remember this semester, and lost a lot of harvest. In the afternoon, I went to the driving school, the coach told me.
“I’ll remember this semester because we lost a lot of harvest,” my coach told me early this afternoon during driving school.
Or
Earlier this afternoon during driving school my coach told me he’d remember this semester because we lost a lot of harvest. (These two sentences were very difficult for me because I wasn’t sure if your coach was talking about the harvest, but hopefully I was able to convey the sentence the way you wanted. Either way you have two options.)
Subject 2 test on July 8, I am very excited, also very nervous, the last time, I was very careless cause didn't pass the exam.
Subject 2 test is on July 8<sup>th</sup>. I’m very excited, but also very nervous, as I didn’t pass the previous exam because I was very careless. (Just more rearranging, but nothing extravagant.)
If lose this chance, I will have more sad.
If I lose this chance, I’ll be depressed. (Because you said “more sad,” “depressed” really provides an understanding of you’d feel like if you didn’t pass the exam.)
Now, I want to say, I can, come on!
Now, all I want to say is “I can. Come on!” (By just adding “all” it emphasizes there’s nothing more to say except “You can!” I separated “I can. Come on,” because it’s a moment to pause to say what you’re thinking, not only to yourself, but also to the readers. It states where you mind is for the conclusion of the title <em>Today</em>.)