Past Simple affirmative & negative sentences

We really___________ (enjoy) the game last Sunday.

They _____________ (not play) very well yesterday. They lost the match.

Sandra___________ (not want) to go rowing with me.

I____________ (buy) a new baseball cap last week.

James_________ (stop) his car in front of the sports shops.

I _____________ (do) my maths homework yesterday.

They ___________ (visit) a farm two weeks ago.

Jenny and Peggy ______________ (not, help) their brother.

He _________ (not, drink) milk at school.

What's the past simple form of UNDERSTAND?