It's not a good idea to travel during the rush hour

1. It's not a good idea to travel during the rush hour
-> We 
2. It's careless of you to walk home alone at night
-> You should
3. Because of the bad weather at the moment, we will start a little bit late  
-> If the
4. You should practice your speaking skill more regularly
-> It I
5. If I were you, I wouldn't tell him the truth about his father 
-> You