They left for the airport as soon as they ________ their bags.

• As soon as এর পূর্বে past indefinite tense থাকলে এরপরেও past indefinite tense হয়।
- যেহেতু উল্লেখিত প্রশ্নে as soon as এর পূর্বে past indefinite tense, তাই এর এর পরের অংশেও past indefinite হবে।

- তাই নিয়মানুযায়ী সঠিক উত্তর হবে - packed.
- Complete Sentence: They left for the airport as soon as they packed their bags.

অন্যদিকে, 
• Future Indefinite Tense + As soon as + Present Indefinite Tense
- Example sentence: I shall ring you up as soon as I arrive.