Choose the best item. (5 points) 1)did she swim/swam in the lake in summer?

1. Did she swim in the lake in summer?

Swim

We form questions in past simple by putting auxiliary
DID in the beggining of the sentence and instead of using verb in it's past form we use it's INFINITIVE.
so we get:
Did  I/you/he/she/it/we/they walk?