Here’s the completed dialogue with appropriate phrases:

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Nhi: Hi, Thanh! What are you reading?
Thanh: Oh, I see. You’ll give a lecture on ethnic minorities, won’t you?
Nhi: Exactly.
Nhi: What have you learned so far?
Thanh: Let me help you to revise it.
Nhi: Well, where do the Nung live?
Thanh: They mostly live in the northern provinces.
Nhi: What is the population of the Nung?
Thanh: About 1 million people.
Nhi: Do they live in stilt houses?
Thanh: Yes. But they also live in earthen houses, and half stilt-half earth houses.
Nhi: What is their main source of living?
Thanh: It’s growing wet rice.
Nhi: How many festivals do they have in a year?
Thanh: They celebrate many festivals in a year, but “Lung Tung” is the most famous one.
Nhi: All correct! You did study hard. Take a rest. Let’s go out for a drink.
Thanh: Let’s go.

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