Select the most appropriate option to fill in the blank.

As soon as she opened the cages, the birds __________.

flew away

The most appropriate option to fill in the blank is flew away.

The sentence is in the past tense, and the verb "to fly" needs the past tense form. The past tense form of "to fly" is "flew."

The other options are not grammatically correct.

• Flown away is the past participle form of the verb "to fly." It is not the correct tense to use in this sentence, because the speaker is talking about something that happened in the past, but not about something that happened before another event in the past.
• Fly away is the infinitive form of the verb "to fly." It is not the correct tense to use in this sentence, because the speaker is talking about something that happened in the past.
• Flies away is the present tense form of the verb "to fly." It is not the correct tense to use in this sentence, because the speaker is talking about something that happened in the past.