Review the item:
While Allison gripped the roof's edge, she no longer resented the many hours that her boyfriend Chris spent in the gym. After all, his strong arms would catch her when she loosened her grip and __________ to the ground below.

The blank requires the simple past of fall, an irregular verb. Fell is the correct form.

Verb Simple
Present
Simple
Past
Past
Participle
fall fall(s) fell fallen

Had fallen, the form you chose, is the past perfect tense. This tense signifies an action in the past that preceded another action. Such a situation is not occurring in this item. Before you continue, review the rules for irregular verbs.

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