Further expansion of “てもいい” – to express “…not necessary”

Today, we are going to have a further expansion about how to express “…not necessary” by using “てもいい”, which makes us change the form of the phrase.
 
Verb + なくてもいい
 
Let’s have a look at an example.
– お腹がいっぱいだったら、食べなくてもいいよ。(If you are full, you don’t need to eat it.)
 
The following examples are slightly difference. You might need to practice a bit to distinct them.
1: アンさん、明日用事があるなら、行かなくてもいいよ。(Ann, if you have something else to do, then you don’t need to go tomorrow.)
2: アンさん、明日行かなくてもいいよ。(Ann, you don’t need to go tomorrow.)
 
1 means Ann is given options to choose to go or not which means Ann has the right to decide. In contrast, 2 is showing a polite way to ban Ann from going.
 
Have a good weekend. See you next time.