Question

1)I should have studied harder.
He studied/didn't study hard.
2) I should have joined the school band.
She joined/didn't join the band.
3) I shouldn't have been so mean to Jimmy.
He was/wasn't mean to Jimmy.
4) I shouldn't have chosen physics and chemistry.
She chose/ didn't choose physics.

Answer 1

1) I should have studied harder.

He didn't study hard.

2) I should have joined the school band.

She didn't join the band.

3) I shouldn't have been so mean to Jimmy.

He was mean to Jimmy.

4) I shouldn't have chosen physics and chemistry.

She chose physics.