Underline the correct words to complete the sentences.

(Gạch chân từ đúng đẻ hoan thành câu)

1. What were you trying to tell me when we bought/were buying the groceries?

2. I found these photos while I arranged /was arranging some English books on the shelf

3. The teacher was explaining the lesson when he dropped /was dropping the microphone.

4. We ran/were running a marathon in Ho Chi Minh City when we met an old friend.

5. While Nam was giving his besriend some tips to pass the driving test, we waited /were waiting patiently outside