Boss: do you think they understood and get a lot from your training?
Me: I covered a lot of stuff and I spent a lot of time to prepare this.
Boss: I saw people sit on the back were completed lost and some people were on the internet. You did not even have eye contact to your audience.
Me: it is not my fault if they were on the internet. If I were looking at my training materials, when I will have time to look at them?
Boss: you spoke too fast. You already know all these concepts. You should just talk with any training materials. If you lost your audience in the first 10 minutes, they will get nothing from your training. Training is the basic skill for presentation. You need to improve your communication skill and let people know your knowledge.