@StanHolt Thank you. I totally missed "the only" on the list as well and got the question wrong.

Can someone plsz simplify this. I am absolutely lost!

This gave me a headache :(

Hopefully, this doesn't confuse you more. But the word "not" still holds it's meaning. You have to still read for context and substance. For example:

Unless a railroad serves its customers well, it will not be a successful business( THIS LAST SENTENCE IS STILL SAYING SOMETHING IS NOT GOING TO OCCUR).

("unless" is apart of group 3 so,

(we'll pick an idea and negate it)

Unless a railroad Serves its Customers Well; lets abbreviate it as " SCW"

it will to be a Successful Business; lets abbreviate it as " SB or simply write it out

Step 1: Apply new learned rule(pick something and negate because we see the term unless right?

/SCW ->

Step 2: the sentence tells us something is "not"( it doesn't say it will be successful)

so we're going to apply the / (reading the actual context)

/SB(successful business)

Step 3: Put it together

/SCW-> /SB (reread the actual sentence and then look at how you just shortened it)

Not sure if this makes sense for you, so i don't want to go too much further with contrapositive. But i truly hope this helps :)

I just wish he would focus on the examples initially provided and not go onto another example:(

I like the way you broke this down!