Where all the scars from the nevers & maybes die

He maketh me to lie down in green pastures; he leadeth me beside the still waters.

#2: "hi [professor], hope you're doing well! unfortunately, I'm [sick/stuck at work/dead] and won't be able to submit [assignment] by [due date]. could I please have an extension? if not, is there anything else I could do to make up this credit? thanks so much, [op]"

The FIRST SENTENCE is the thing you want the recipient to do. Do not make them guess.

I want to let you know about ... (This email is to inform someone of something not to ask them to do anything)

Could you please do ... (This is a request. You want them to do something).

I'm looking into x and wondering if you can help me (this is also a request but for information instead of an action).

People do not want to read an email and even if they do read it, most people are skimming and not interested. Tell them what you want first, then provide context or other information (when you need a thing is often key). If the email is informational, you can even add "you don't need to do anything, this is just to keep you informed!" People will appreciate not having to figure out what you want from them.

If you can't articulate what you want the recipient to do with the message, you are not ready to email them. I read too many emails where I have no idea what the person wants from me.