Verb conjugation of "brake" in English

Regarding the meeting in early May: I could not reschedule the appointment at my daughter's doctor and I will definitely know if I can come during the first 2 weeks. I guess we should talk next week.
You have to be careful when you go on summer vacation. There are many dangers but the most dangerous one is the sun itself, because if you're not careful it may harm you. People underestimate the rays.
Maybe it's just a small mistake but I think that we corrected almost all errors. But I'm not worried anyway, because you already have good language skills. Good luck with your exams tomorrow.