Review the item:
Christine sprang out of the bed and saw bright sunlight streaming through the windows. She knew that Professor Armour would not tolerate another late, so Christine leapt back under the covers and sleapt until noon.

The third verb, sleapt, is the problem. The sentence requires the simple past. Slept is the correctly spelled form.

Verb Simple
Present
Simple
Past
Past
Participle
sleep sleep(s) slept slept

Sprang, the verb you chose, is perfectly correct. Before you continue, review the rules for irregular verbs.

Go back to the item to try again.