“I will serve the rice” vs “I am going to serve the rice”
I’m doing reverse tree, and think that more attention should be given to the difference between the Simple Future and the “Going to do” future. In the unit they seem to be interchangeable, but they are not. Simple future can be a spontaneous decision. ( “ you serve the veges and I’ll serve the rice, ok?”) “Going to” implies a previous decision or plan. ( ok, that’s settled. Joe is going to serve the veges and I’m going to serve the rice.”)
Would it be possible/useful to make an extra exercise to practise the difference? Or is it not so important In the Great Scheme of Things Linguistic and Grammatical? ;-))
Technically true, but for all practical intents and purposes (and for beginners), they're pretty much interchangeable. Will can also be used as a promise for the future, going to can be used spontaneously (I'm going to go get the weights so we can work out, said in the moment)
I always tell my ESL students (usually all Spanish speakers) to use will when they would use the simple future, and be+going to when they would use ir a. Any explanation using planning versus spontaneity immediately runs into exceptions because of the way we actually use them.
I'd say the distinction is probably "not so important in the Great Scheme of Things Linguistic and Grammatical." When speaking, you can probably get by using the Ir + infinitive form all the time. I suspect that Duolingo doesn't teach simple future much in Spanish because it's not as common. However, it's a good idea to be able to recognize simple future. There are probably other resources for practicing it.