A couple of those aren’t particularly fair because you’d never actually use “I slept tonight” in most cases. It’d be “I will sleep tonight/I slept last night”. The individual verbs aren’t meant to be interchangeable like that, they vary based on the nouns they’re referring to and the perspective.
Not to say it isn’t confusing or inconsistent, but there is a larger grammatical pattern at play that you learn over time.
That last one’s not entirely fair; it should be “I have to study”
English is still pretty inconsistent with some of its verbs though
A couple of those aren’t particularly fair because you’d never actually use “I slept tonight” in most cases. It’d be “I will sleep tonight/I slept last night”. The individual verbs aren’t meant to be interchangeable like that, they vary based on the nouns they’re referring to and the perspective.
Not to say it isn’t confusing or inconsistent, but there is a larger grammatical pattern at play that you learn over time.