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
