Read the following dialogue! Then answer the question!

Mr. Surya gives additional times to Zahra and Rachel to prepare for the English Competition next week.

Mr. Surya: Zahra, where Is Rachel? It's three o'clock. We should start the additional lesson.

Zahra: Rachel is going to the canteen, Sir. She needs to buy some drinks.

Rachel is back from the canteen.

Rachel: Excuse me, Sir. I am sorry, I've been from the canteen to buy some drinks

Mr. Surya: It's all right, Rachel. Let's start the lesson!

Mr. Surya is explaining the lesson to Zahra and Rachel. He explains about recount text.

Mr. Surya: Recount text tells us about what had happened in series of event in sequence, It uses Simple Past Tense. Do you know what I mean?

Rachel: I'm not sure I get your point, Sir. What is Simple Past Tense?

Mr. Surya: l'll tell you about it. Simple Past Tense is a tense used to talk about action in the past.

Rachel: Oh, I got it. Sir. Thanks for your explanation!

Mr. Surya: What about you, Zahra? Do you understand?

Zahra: Yes, Sir. I understand it.

Mr. Surya: Okay. Let's do the exercises!

Why does Mr. Surya give additional times to his both students?