Base form

Simple past

Past participle

I bring my lunch.

I brought it to school.

I have brought it already.

Base form

Simple past

Past participle

I buy a ticket.

We bought a ticket yesterday.

I have bought it online.

Base form

Simple past

Past participle

I catch the bus at 8.

She caught the last train.

I have caught the flu.

Base form

Simple past

Past participle

They fight in movies.

We fought a hard game.

They have fought many battles.

Base form

Simple past

Past participle

I seek help when I need it.

She sought a new job.

They have sought a solution.

Base form

Simple past

Past participle

My teacher teaches English.

He taught us math.

She has taught this class for years.