@16dnholli

I also got a bit tripped up by this at first, but when doing group 4, you should never include 'cannot' in your negation. You only look at what 'cannot' is modifying and negate that.

So in this case, I am singling out being happy as one of the conditions. That would give me these two correct translations.

Serious financial problems --> /happy

Happy --> /Serious financial problems

Hope this helps.

@MGonz6

It all has to do with the meaning of the indicators themselves, and what they imply. The difference is highly important because for example, if you were to say "I will not shower unless I eat something first", and you correctly negated the sufficient, you would get the answer:

Shower --> Eat something first

/Eat something first --> /Shower

If I tried to negate the necessary instead, I would end up with the following:

/Shower --> /Eat something first

Eat something first --> Shower

As you can see, mistakenly applying the wrong rules gets you results that confuse the sufficient for the necessary. It entirely hinges on the word 'unless'.

In my example, "I will not shower unless I eat something first", I can rephrase it in my mind to say:

If I do not eat something first, then I will not take a shower. OR I will take a shower only if I eat something first.

As you can see, this is the same as our correct translations from above, where we negated the sufficient.

It would not make sense to try to rephrase it to say something like,

If I eat something first, I will take a shower.

For all we know, I could eat something and still chose to not take a shower. But we know for a fact that if I do shower, then I did eat something first.

In one of our examples from this lesson, "Lazy cats never develop heart disease",

I can rephrase it in my mind to mean "If I am a lazy cat then I will not develop heart disease", "All lazy cats do not develop heart disease", etc.

As you can see, I am negating the necessary when I am rephrasing this in my mind, and this is entirely because of what the word 'never' is implying in the sentence.

I hope this helps!

Hoping to get a little clarity on when using 'or' vs. 'either/or' affects the overall meaning? In the first example, "You must sit at either one end of the table or the other", it was said that the removal of 'either' did not affect the meaning, given that you must sit at one end and its not possible to sit at both. But in which instances does the use of 'either/or' vs. just 'or' impact the meaning? Could it ever just be 'either' with no 'or'? Thanks!