I've been doing some reading for the Goethe Institut, and whenever they tell me to do something they use the word "Sie", for instance:

> 
> Wir geben Ihnen mehr Informationen. Finden Sie die passenden Fragen.
> 
> 
> 

or 

> 
> Bitte setzen Sie die Verben im Präsens ein.
> 
> 
> 

I'm especially curious since it seems totally unnecessary to write "Sie" in the contexts in which they were used.