That’s opposite of what I usually said or heard. 校 usually means to correct something in Mandarin , like a watch. 朝早 is never used in Mandarin. The most colloquial version is “我定了早上7点的闹钟”.In real life, it seems I almost always heard:
Unless the Cantonese speaker is deliberate uttering it in standard Chinese?
You'd better write "in Mandarin" or "in Cantonese" instead of "in Chinese" in future, much difference between the both languages.大家好！
I know this question is fairly basic, but I'm not sure how to say it. How would you say "I set my alarm for 7 am" in Chinese?