Question

Susan ........ (Run) to school because she was late.

Answer 1

Susan ran to school because she was late. Past tense of Run is Ran.

Answer 2

Run is in present tense. We need something that is past tense because it says she was late.

So:

Run - present tense
Will run - future tense
Ran - past tense

So to complete that blank, it would be ran.