Are these deductive argument valid?

Either you go to a university or you don't. If you're in university you will have time for nothing else but study. If you're not in university then you're wasting your time. So either you stop wasting your time or you start to make time to do something else besides your study. (Invalid)

Either you don't participate in class or you don't collaborate with your team members. If you are a valuable asset to your school, then you participate in class. If you are a valuable asset to your team, then you collaborate with your team members. So you are not a valuable asset to either your school or your team. (Invalid)

Only graduates with Critical Thinking skills are sought after by employers. After you graduate you will have Critical Thinking skills. So you will be sought after by employers! (Valid)

All university students in US have to do internships. Some university students in US go abroad for their internships. So some Harvard students go abroad for their internships. (Valid)