@emmorens932 thank you!!

'Unpleasant criticism provides motive'

If it 'provides' motive then it is 'sufficient' for motive or 'guarantees' motive (however you want to think about it)

I find it can be helpful in some cases to think about the actual meaning of a statement than to adhere strictly to the logical indicators.

I saw an example of this on a previous question on this section (question #22) in A.C. B "It is wrong for a person who understands the difference between right and wrong to intentionally harm another person"

One person pointed out that "who" isn't an official group #1 logical indicator - however - if you think about the meaning of the sentence - I translated it to: When one understands the difference between ...., it is wrong'.

'One cannot maintain good soil without good farming'

You can choose to either use 'cannot' as group 4 negate necessary or 'without' group 3 negate sufficient as your logical indicator

When JY said understand 'without' as a negation I believe he meant that when using group 4 'cannot' as your logical indicator - don't forget that prior to your negate, necessary, 'good farming' would carry a negation with it so:

Before negate, necessary:

Maintain good soil → /good farming

Negate, necessary:

Maintain good soil → good farming

You can also use group 3 negate sufficient: "without"

Before negate, sufficient:

/Maintain good soil → good farming

Negate, sufficient:

Maintain good soil → good farming