Составь прдложение school were at they yesterday

School at they were yesterday

They  were  at  school  yesterday (это утвердительное предложение! ) were they at school yesterday? (вопросительное предложение! )

1)a teacher works at school. 2)workers work at plants and factories. 3)a businessman works at office. 4)doctors work at hospitals. 5)an economist works everywhere. 6)a dentist works at stomatological polyclinic. 7)engineers at design bureaus.