איך בונים משפט חיוב של past progressive?

מבנה המשפט: משפט חיוב: subject- verb be- verb- ing (The teacher is standing in class)
משפט שלילה: subject- verb be- not- verb- ing(The teacher is not standing in class)
משפט שאלה: verb be- subject- verb- ing (?(is the teacher standing in class
משפט שאלת מידע: Wh- verb be- subject- verb- ing (where is the teacher standing?)
ככה?