Question

1. this is a pretty crazy day we need to go to bed and wake up again.

this is a pretty crazy day, we need to go to bed and wake up again.
correct as is
this is a pretty crazy day, so we need to go to bed and wake up again.
this is a pretty crazy day so we need to go to bed and wake up again.

Explanation:

The original sentence "This is a pretty crazy day we need to go to bed and wake up again" is a run - on sentence (two independent clauses joined without proper punctuation or a conjunction). The option "This is a pretty crazy day, so we need to go to bed and wake up again" uses a comma and the conjunction "so" to properly connect the two independent clauses, showing the cause - effect relationship. The first option just adds a comma, which still creates a comma splice. The "correct as is" option is wrong as the original is a run - on.

Answer:

This is a pretty crazy day, so we need to go to bed and wake up again.