After class started, everyone put down their phones and opened their computers, only to start looking at their phones again.

When the teacher entered the classroom, he didn't say anything. He stood on the podium, glanced at the number of people in the classroom, then sat down and started doing his own work.

The teacher didn't specify what to do because he had already mentioned it last week.

The data measured at the Yi family last week was what they needed to draw now.