Usually when you have a student or students that aren't focused there is a reason for it. Either there are personal problems ar perhaps they just have no interest in the topic you are presenting. As a facilitator, you need to identify these students early on before it effects there grade or perhaps the rest of the class. If you can relate the topic to something that may interest them or tailor parts of the topic to various situations that may interest said students they will become more enguaged. Sometimes if you have a student with personal issues and they are willing to talk to you about them then you can give situations that other people had to overcome and let them know it is tough to concentrate when there are other situations going on. But there are times where you have to seperate school/work from personal issues. If the issues are bad enough, let them know that schools have counselors to help them through.