How do teachers teach contagiously?

Because the teacher’s lectures are passionate, ups and downs, rhythmic, full of sound and shape, cordial and sincere, they can have a certain impact and attract the full attention of the whole class. We all have experience. When we recall when we were studying, which teacher was good and which teacher was bad, we have many deep impressions. When a certain teacher lectures, he is cadenced and high-spirited, just like acting. Which teacher just reads from the script in class, is sluggish and doesn't like to listen, so it is very important for teachers to lecture with cadence.