Which sentence is correct?

This is an unique case

This is a unique case

This is a very unique case

This is the most unique case

A drowning man catches at a straw.

Do not tell the lie.

He told me a fool.

I do not know to swim.

I lodged a complaint

I made a complain

I lodged a complained

Do not complaint any more

You are an M.B.B.S

He was an M.A

He is an L.M.F

All of them

You had better going there

You had better go there

You had better gone there

You had better to be going there

I do not know to swim

He told me a fool

A drowning man catches at a straw

He said a lie